Email signature: what belongs in it and what quietly costs you

An email signature is the block appended to the end of your messages: who you are, how to reach you, and whatever the company requires. It is the most frequently transmitted piece of design a small business owns — every person, every message, every day — which makes it worth ten minutes of thought and explains why the badly built ones do so much quiet damage.

The failure is rarely aesthetic. It is that the signature contains six lines nobody reads, an image that does not load, a banner that renders as a broken box on a phone, and a legal paragraph longer than most of the emails it follows.

What an email signature should contain

• Your name and what you do — the role in plain words rather than an internal job title.
• The company name, and a link to the site.
• One reliable way to reach you besides email. One, not three.
• Anything legally required where you operate — several jurisdictions require company registration details on business correspondence.
• Nothing else, unless it earns its place. A single line promoting one specific thing beats a row of icons nobody clicks.

Four to six lines is the working limit. Every additional element competes with the message above it, and in a reply chain the signature repeats — a ten-line block turns a three-message exchange into a page of contact details with fragments of conversation between them.

Why signatures break

Email clients render HTML inconsistently, and the ones used in business are the strictest. Images referenced from a server can be blocked by default, so a signature that is entirely one image shows as an empty rectangle to a meaningful share of recipients — and often to the exact corporate recipients you most want to impress. Logos attached as files appear as paperclips, which makes every message look like it carries an attachment.

Social icons deserve the same scrutiny. Six small images, each a separate request, each capable of being blocked, decorating a link nobody clicks. If the icons matter, use text links; if they do not, remove them.

Building one that works everywhere

1. Draft it as plain text first. If it fails to communicate without formatting, formatting will not rescue it.
2. Keep it to four to six lines and one accent colour at most.
3. Avoid images where you can. If a logo is required, keep it small and give it alt text.
4. Never put contact details only in an image — blocked images then hide your phone number.
5. Test in the clients your recipients actually use, including a phone and one strict corporate client, in dark mode as well.
6. Use a short second version for replies, so chains stay readable.
7. Check what your jurisdiction requires on business correspondence — several mandate registration details, and the requirement usually applies to email too.
8. Standardise the format across the team, and let people fill in their own details.

The disclaimer question

Long confidentiality notices are traditional and largely ineffective: a paragraph asserting that an accidental recipient must delete the message and forget it has weak standing in most jurisdictions, and it appears after the content it is supposedly protecting. Where legal counsel requires one, keep it short and put it last. Where it is habit rather than advice, consider dropping it.

Regulatory details are a different matter. Requirements to state a registered company number, registered office or VAT identifier on business correspondence exist in many countries and often cover email explicitly. That is worth checking rather than assuming, and it is the one part of a signature that is not a design decision.

Keeping it consistent

Ettex Mail lets each mailbox on your domain carry its own signature, so the format stays the same across the team while the details differ per person, and replies can use a shorter version. Since it runs on your own domain, the address in the signature matches the address it was sent from — which sounds trivial and is the first thing a cautious recipient checks.

There is no signature designer: no drag-and-drop builder, no template gallery, no central management that pushes a signature to everyone or updates a banner across the company. The block is HTML or text you set per mailbox. For a company that wants campaign banners centrally controlled across hundreds of users, dedicated signature-management software exists and does that properly.

Six lines at most, no contact detail that lives only inside an image, one accent colour, a shorter version for replies — and check what your country requires before deciding what to cut.