What an email signature must contain

2026-01-14

A professional email signature is much more than just a digital business card or a marketing banner. It is a legally relevant document. Companies operating internationally must comply with a variety of different laws — ranging from Germany's legal disclosure requirements and the US CAN-SPAM Act to formal requirements in Australia and cultural specifics in China.

If you want to secure your corporate email communication globally, an "Ultimate Signature" is essential. Here is a breakdown of the mandatory information you must consider in the world's most important economic regions.

🔗Section 1: The Formalists: Germany, Austria, Switzerland, and the EU

The strictest rules for the signature text itself are often found in Central Europe. The focus is on the complete legal identification of the sending company.

🔗Germany (HGB & GmbHG)

The signature must fulfill the Imprint Obligation (Impressumspflicht) and contain the following information, depending on the legal form:

Legal Form (e.g., GmbH, UG, AG)	Mandatory Information
Company Name	Exactly as entered in the Commercial Register.
Legal Form	(e.g., GmbH, UG (haftungsbeschränkt), AG).
Registered Office	The location where the company is registered.
Registry Court	The competent local court (Amtsgericht).
Commercial Register Number (HRB/HRA)	The complete number.
Authorized Representatives	All Managing Directors, Board Members, or Supervisory Board Chairmen with full names.

Important: Providing an email address and telephone number is also mandatory to ensure rapid contact.

🔗Austria (UGB) and Switzerland

Similar to Germany, the disclosure of the Commercial Register Number (Austria/Switzerland) and the complete legal form is required.

In Switzerland, the requirements are regulated in the Swiss Code of Obligations (CO).

In Austria, the regulations are scattered across at least five laws, which is why the Austrian Federal Economic Chamber (WKO) provides a comprehensive checklist.

🔗The anti-spam focus: USA and Canada

In North America, less emphasis is placed on register data and more on controlling promotional emails (spam prevention).

🔗USA (CAN-SPAM Act)

This law applies as soon as the email is classified as "commercial". The central requirements for the sender are:

Physical address: The email must contain a valid physical mailing address of the sender (business premises or PO Box).
Opt-out mechanism: There must be a clear and functional unsubscribe link. Opt-out requests must be processed within 10 business days.
Identification: The email headers and subject line must not be misleading.

🔗Canada (CASL – Canada's Anti-Spam Legislation)

CASL is one of the world's strictest anti-spam laws, based on a strict opt-in principle. The signature must:

Clearly state the identity of the sender and the organization.
Include a postal address.
Offer a working unsubscribe link that processes opt-outs within 10 business days.

🔗APAC: Australia and China

These regions offer a blend of Anglo-Saxon regulation and cultural necessities.

🔗Australia (Corporations Act & Spam Act)

Australia combines anti-spam rules with a formal registration obligation:

ABN/ACN: The signature should include the company's Australian Business Number (ABN) or Australian Company Number (ACN).
Unsubscribe: An unsubscribe link is mandatory; opt-outs must be implemented particularly quickly (within 5 business days).

🔗China (Cultural Conventions & Laws)

In China, cultural etiquette and relationship building are often more important than the literal law text regarding the footer.

Bilingualism: The signature should ideally be bilingual (English/Chinese) to show respect.
Title and Hierarchy: The employee's position/title is highly important and must be correctly translated and highlighted.
WeChat: Including a WeChat ID or WeChat QR code is essential, as almost all business communication occurs via this app.
USCC (Optional): The disclosure of the Unified Social Credit Code (USCC) is not legally mandated in every email but generates high trust.

Caution for Advertising: If the email contains advertising, the word "AD" (or "广告") must be in the subject line!

🔗Global checklist

To create a single signature that works worldwide, you must combine all mandatory disclosures of the strictest market (Germany) with the anti-spam elements (US/Canada) and the identification numbers (Australia/China).

🔗Must-Haves

Element	Purpose
Full Company Name (incl. Legal Form)	Identification (DE, AT, CH, AU).
Employee Name & Title	Identification and Hierarchy (Global, esp. CN).
Postal Address	Legally Required (US, CA, AU) and Trust (DE, CN).
Commercial Register Number & Court	Imprint Obligation (DE, AT, CH).
Managing Directors/Representation	Imprint Obligation (DE, AT, CH).
ABN/ACN (if relevant)	Registration Obligation (AU).
Working Unsubscribe Link	Anti-Spam (US, CA, AU).

🔗Recommendations

Bilingual information (Name, Title, Address) for Canada (Quebec) and China.
WeChat ID/QR Code for the Asian market.
Liability Disclaimer at the bottom of the email (expected in the US and UK).

By consistently implementing these elements in your email signature management system, you ensure that every email leaving your company is legally secure—no matter where in the world it is sent.