E-Invoicing 2026 in Law Firms: Receipt Is Just the Beginning

A supplier sends the law firm a file with the extension .xml. In the inbox, it looks like a “technical” issue; in accounting, it means extra work; and to the person handling the case, it initially means nothing at all. So a PDF is requested, printed out, or saved separately. While this makes the invoice readable, the intended digital process has already been disrupted upon receipt. 2026 is exactly the right time to correct this process. After all, e-invoicing is not merely a matter of law firms issuing their own invoices. Since January 1, 2025, domestic companies have been required to be able to receive e-invoices. While there are transition periods for issuing e-invoices, the general transition period ends on December 31, 2026. Anyone who has merely set up an additional email inbox at this point meets the minimum technical requirement for access but does not yet have a reliable system for receiving invoices. This article outlines the requirements and highlights the organizational decisions a law firm should make by 2026. It is not a substitute for tax advice in individual cases.

What Qualifies as an E-Invoice Since 2025

As of January 1, 2025, a PDF sent via email is no longer considered an e-invoice for VAT purposes. It is classified as an “other invoice.” An e-invoice must be issued, transmitted, and received in a structured electronic format and must enable electronic processing. In Germany, two formats are particularly widespread:

• XRechnung: a structured XML file without an automatically included PDF preview.
• ZUGFeRD: a hybrid format that can combine structured invoice data with a human-readable representation. According to the BMF FAQ, ZUGFeRD versions 2.0.1 and higher generally meet the requirements, with the exception of the MINIMUM and BASIC-WL profiles. Both formats can implement the European EN 16931 series of standards. What matters is not the file extension alone, but whether the required invoice details are contained in a structured format and can be processed electronically. For law firms, this results in an inconvenient but important rule: An XML file is not merely a technical appendix to a PDF. In the case of hybrid invoices, the structured data section takes precedence. If the XML data and the visible display differ, the structured data is generally considered authoritative. Anyone who checks only the PDF may therefore overlook precisely the part that matters for tax purposes.

The obligation to receive and the obligation to issue are two separate issues

The most common misconception is: “We still have until 2027 or 2028.” This is only partially correct. Receiving: As of January 1, 2025, domestic companies must be able to receive e-invoices. According to the current BMF FAQs, there is no general exception to this requirement. This also applies to small business owners, even though they are exempt from issuing e-invoices for their own services. For the sole purpose of receiving e-invoices, an email inbox is legally sufficient for the time being. Issuing: From January 1, 2025, through December 31, 2026, all invoice issuers may still use other types of invoices for domestic B2B transactions. A paper invoice is permitted during this transition period; however, the recipient’s consent is still required for a simple electronic format such as PDF. If the invoice issuer’s turnover in the previous year did not exceed 800,000 euros, the transition period is extended until the end of 2027. After that, e-invoicing will become the norm for covered domestic B2B transactions. Exceptions apply, among other things, to small-amount invoices up to 250 euros, travel tickets, and services provided by small businesses. Invoices to private end consumers are not subject to the B2B requirement. These differences are not just a footnote. A law firm may still be permitted to send its own fee invoices as PDFs in 2026, but at the same time must be able to accept e-invoices from its IT service providers, landlords, training providers, or other business partners.

Why an Invoice Mailbox Alone Is Not Enough

The Federal Ministry of Finance (BMF) clarifies that an email inbox is sufficient for receiving invoices. However, this does not mean that any generic collection inbox automatically constitutes a sound business process. A robust invoice receipt process must answer at least five questions:

1. What address or interface is provided to suppliers?
2. Who determines whether an incoming file is an e-invoice?
3. How is the structured content made visible and verified for accuracy?
4. Who approves the invoice in terms of content and accounting?
5. Where are the original file, the approval, and the posting reference stored in a traceable manner? If even one of these answers is missing, shadow processes arise. XML files are forwarded to personal email accounts, PDF views are stored separately, or invoice data is re-entered manually. This wastes time and makes it difficult later to determine which file was actually received and verified.

The structured portion must be verifiable

An XRechnung is virtually unreadable to humans without a viewer. This is not a flaw in the format, but part of the concept: the data is intended to be processed by machines. For human review, the law firm therefore needs a visualization tool. The Federal Ministry of Finance (BMF) now refers users to the tax authority’s e-invoice viewer at e-rechnung.elster.de. In addition, there are commercial and free viewers available. When making a selection, the law firm should not only consider an attractive display but also how confidential business data is handled. In particular, the following should be checked:

• Does the visualization take place locally, or is the file uploaded to an external service?
• Are files, metadata, or usage logs stored?
• Can the result be unambiguously linked to the unaltered original file?
• Does the tool recognize XRechnung and supported ZUGFeRD profiles?
• Is there technical validation against format rules? Validation can identify missing or illogical required information. The Federal Ministry of Finance (BMF) considers it useful but does not make it a direct prerequisite for tax recognition. Furthermore, it does not replace a professional invoice review. A formally valid invoice may be addressed to the wrong law firm, include a service that was not ordered, or list an incorrect amount.

A Streamlined Workflow for Small and Medium-Sized Law Firms

A good process doesn’t have to start with a major ERP implementation. For many law firms, a clear, standardized workflow is sufficient to begin with.

1. Establish a Central Inbox

Set up a unique billing address, such as rechnung@kanzlei.de, or use the documented invoice inbox in your accounting software. Inform suppliers which formats and transmission methods are supported. The email account should not be a personal account. Access rights, coverage for absent employees, and staff turnover must remain manageable from an organizational standpoint.

2. Automatically or manually pre-sort incoming invoices

Files should be recognized by type and assigned to the invoice inbox. An XML file must not end up in the general spam or downloads folder. At the same time, caution is advised with attachments: Invoices are a known entry point for malware. File verification and secure display therefore go hand in hand.

3. Preserve the Original Unaltered

Retain at least the structured portion in its original, unaltered form. A generated PDF view does not replace the XML file. If a file is converted or formatted for internal systems, it should remain clear which original served as the basis.

4. Separate technical and business-related reviews

The technical review answers: Is the format readable, plausible, and, if applicable, valid? The business-related review answers: Was the service commissioned and performed; are the amount, service period, client or cost center, and payee correct? In small teams, these roles may overlap. Nevertheless, the review steps should be documented separately so that a green checkmark does not necessarily mean both “file could be opened” and “payment approved.”

5. Link Approval and Posting

The invoice should remain linked to its approval status, the person responsible, and the posting. Manual printouts with handwritten abbreviations are technically possible but create a parallel audit trail. A digital audit trail that links the original, visualization, decision, and posting is preferable.

6. Define Error Scenarios

Specify what happens in cases of damaged files, missing required information, discrepancies between XML and PDF, or unclear services. Do not reflexively request “another PDF.” Depending on the error, a corrected e-invoice may be required. Although there is still some leeway during the transition periods, the process should already be prepared for the standard procedure that will apply later.

Retention: The PDF View Is Not the Original

According to Section 14b(1) of the German Value-Added Tax Act (UStG), incoming and outgoing invoices must generally be retained for eight years. For e-invoices, at least the structured portion must be stored in such a way that it remains intact in its original form. In addition, the general requirements for electronic records and data access remain relevant. Section 147 of the German Fiscal Code (AO) allows tax authorities, under certain conditions, to inspect stored data or request machine-readable data. The GoBD emphasizes traceability, verifiability, completeness, accuracy, timely recording, order, and immutability. In practice, this does not mean that every law firm must immediately purchase a new archiving system. However, it must be able to explain:

• where the original file is located,
• how subsequent changes are prevented or made traceable,
• how the invoice can be retrieved and made readable,
• how it relates to posting and approval,
• and how access is maintained during the retention period. A folder full of renamed PDFs does not answer these questions if the original XML data is missing.

Don’t Sacrifice Data Protection and Security for Convenience

E-invoices regularly contain contact information, bank details, service descriptions, and internal identification codes. For law firms, these descriptions may also reveal information about client matters or sensitive internal processes. Therefore, a free online viewer should not be chosen solely based on ease of use. If files are transferred to an external service, the data flow, the provider’s role, the storage location, deletion procedures, and technical safeguards must be reviewed. For particularly sensitive invoices, a local or controlled solution may be preferable. Access permissions also deserve attention. Not everyone with access to the firm’s general mailbox needs to view all invoices. Conversely, the process must not depend on a single person who might be on vacation or sick.

What the Law Firm Should Decide by 2026

The transition period should be used not as a delay, but as a testing window. By the end of the year, at least the following decisions should have been made:

• Which central channel will be used for e-invoices?
• Which formats can the law firm read, validate, and archive?
• Who will be responsible for technical verification, substantive approval, and representation?
• How will the original file remain linked to the accounting entry and decision?
• Which software should generate the firm’s own e-invoices starting from the relevant date for the firm?
• How will clients or business customers be informed about the future invoice format? Those who test these questions now using actual incoming invoices will identify missing permissions, unsuitable viewers, and media breaks even during the transition period. Digital law firm platforms such as Jurono can help organize commercial and operational processes more clearly. However, the specific tax-related invoice processing, validation, and archiving must be coordinated with the accounting and document management systems actually in use.

Conclusion: Receipt Is Technology; Processing Is Organization

The legal requirement for receiving invoices can be met with an email inbox. A reliable invoice receipt process, however, is only achieved through defined responsibilities, visualization, verification, approval, and unaltered storage. 2026 is the logical time for law firms to standardize this process—not because every transition period ends immediately, but because genuine e-invoices are already being received and the general leeway for other outgoing invoices expires at the end of the year. Use the next incoming e-invoice as a test case: Can your team view the structured content, approve it from a technical standpoint, archive it securely, and retrieve it unambiguously later? If the answer to any of these questions is “no,” the problem isn’t a lack of XML training—it’s the absence of a clear process.

Sources

• Federal Ministry of Finance: Questions and Answers on E-Invoicing, as of March 2026 – definition, exceptions, formats, receipt, transition periods, and retention; accessed August 7, 2026.
• Federal Ministry of Finance: Introduction of Mandatory E-Invoicing, Letter dated October 15, 2025 – current administrative interpretation and amendment to the Value-Added Tax Application Decree; accessed August 7, 2026.
• Section 14 of the German Value-Added Tax Act (UStG) – legal definition and requirements for invoices; accessed August 7, 2026.
• Section 147 of the German Fiscal Code (AO) with implementing decree – Retention and data access; accessed on August 7, 2026.

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• GDPR in Law Firms: Practical Checkpoints for New Tools
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• Switching Law Firm Software Without Lock-in: Your Rights Under the EU Data Act Next Step: Document the invoice receipt process from the mailbox all the way to posting. Every step where a file is manually copied, renamed, or re-entered is a prime candidate for streamlining.