An email signature is seen more often than almost any ad a small business will run, and by the people most likely to buy. Yet it is often put together in 5 minutes and never reviewed. Depending on the type of message, the company's location and the industry, it may also need to include specific legal information. This guide covers what to check, what to leave out, a layout that stays intact in Outlook, and a way to build the signature once and share it with the whole team.
What information may be required
The United States has no single equivalent to the UK's Companies Act email disclosure rules. Requirements can depend on state law, industry regulations and the type of email. Marketing emails are also subject to rules that do not necessarily apply to ordinary 1-to-1 business correspondence. If your business is registered in the UK, the Companies Act 2006 and the Companies (Trading Disclosures) Regulations 2008 treat business emails as business letters. A limited company, PLC or LLP must show:
- the registered company name, exactly as it appears in the official company register;
- the company registration number;
- the place of registration, such as "Registered in England and Wales" or "Registered in Scotland";
- the registered office address, which may differ from the operating address.
For businesses covered by those UK rules, the requirement applies to every business email sent outside the company, including replies, and to every employee who sends them. Failure to comply can lead to a fine, and it may allow a customer to argue that they did not know which legal entity they were dealing with. A VAT number is not required in emails, although it is required on VAT invoices. Sole proprietors and partnerships fall outside those regulations, but a sole proprietor using a business name should still provide their own name and an address for service. US businesses should check the federal, state and industry rules that apply to their messages.
Put any required legal information at the bottom in small text, using 1 or 2 lines. For a US business, that might include the legal entity name and business address. A UK-registered company might use: "Nook Coffee Ltd, registered in England and Wales, company number 12345678. Registered office 1 Example Street, Leeds LS1 1AA." That wording is complete under the rules described above.
What to include, in order
- Your name, followed by your job title.
- The company name, or the logo with the company name as alt text.
- 1 phone number.
- 1 link. A bio link page works well here because it can hold your website, booking page, social accounts and a vCard behind a single address, keeping the signature short.
- Any required legal information.
5 lines plus the legal line are enough. Anything else competes with the message you actually wrote.
What to leave out
- Inspirational quotes and taglines.
- A row of 6 social icons. A single link to a page that lists them does the same job and works in every email client.
- Large images, banners and scanned handwritten signatures. Many email clients block images by default, leaving the reader with a broken box.
- Long confidentiality disclaimers. They often carry little legal weight and push important company information off the screen. If your industry expects one, keep it to 1 sentence.
- "Sent from my phone" apologies. Set up the same signature on your phone instead.
A layout that works in Outlook and on phones
- Use text, not a picture. A signature saved as 1 image cannot be copied, searched or read by screen readers, and many inboxes block it by default.
- Keep it narrow. A width of about 320 pixels displays well on a phone without wrapping. Most email is now opened on a phone.
- Use web-safe fonts. Arial, Helvetica, Georgia or Verdana. If a brand font is not installed on the recipient's device, it will be replaced with a font you did not choose.
- Use 1 small logo with alt text. Keep it under 30 KB and use a transparent background so it works in dark mode. The Image optimizer can reduce it to the right size.
- Account for dark mode. Avoid pure white text and pure black backgrounds in the signature itself. Let the email client set them.
- Do not use attachments. A logo added as an attachment appears as a file on every email you send.
Build it once with the signature builder
The email signature builder in the Digily Link dashboard creates a signature from a template. Enter the name, job title, phone number, logo, link and social icons, choose a theme, preview the result, then copy the HTML or export it. The free plan includes 5 signatures, Starter includes 25 and Pro includes 50, enough to give each team member their own version of the same design. On paid plans, signatures can be assigned to projects, with 1 per client if you run an agency.
Paste the HTML into the signature settings in Gmail, Outlook, Apple Mail or your phone's email app. If you want a quick version without an account, the free Signature generator builds a simple signature in your browser.
Measure the link
A signature link is a marketing channel, so treat it like one. Use a short link, such as digily.bio/yourname, so you can change its destination later without asking the whole team to update their signatures. Tag the destination with the UTM link generator, using utm_source=signature and utm_medium=email. The statistics will then show how many clicks the signature generates each month, which is often more than the social accounts combined.
If you also meet people in person, consider adding a vCard QR code to the signature, as described in the guide to vCard QR codes for business cards. Keep it small, and remember that images may be blocked, so the text link still needs to work on its own.
Frequently asked questions
Do sole proprietors need legal information in an email signature?
The UK Companies Act rules apply to registered companies and LLPs, not sole proprietors. In the United States, requirements vary by state, industry and message type. A sole proprietor operating under a business name should still provide their own name and a business address. It is also good practice because it helps establish trust.
Do the rules apply to internal emails and replies?
Under the UK rules described above, they do not apply to internal emails. They do apply to replies sent outside the company because those messages are still treated as business letters. US requirements depend on the applicable law and the type of message.
What if the business is registered in Scotland or Northern Ireland?
The same UK rules apply, but the wording changes. Use "Registered in Scotland" with the SC number, or "Registered in Northern Ireland" with the NI number.
Can I put the legal information only on the first email?
Not if the rules governing your business require it on every business email. That is why the information belongs in the signature instead of being typed by hand.
How do I give everyone on the team the same signature?
Build 1 design in the signature builder, duplicate it for each person with their name and number, and send each person their HTML. When company details change, update the template and send the new version once.
Final checks
- The legal name, registration details and business address required for your company are all present.
- The signature uses text with 1 small logo and is under 320 pixels wide.
- It contains 1 link, and that link is a short link you can change later.
- It displays correctly in Gmail, Outlook and on a phone, in both light and dark mode.
- Everyone in the company is using the same version.
