Every business eventually discovers that it has fourteen versions of its own email signature. Three fonts, two logos, one person who still has the old office address and somebody whose job title has not been correct since 2023.

It is a small thing that is visible on every message the business sends, which makes it worth fixing properly once.

What UK law requires

Start here, because a surprising number of business signatures are non-compliant.

A UK limited company must state on its business emails:

  • The registered company name
  • The company registration number
  • The place of registration — England and Wales, Scotland, or Northern Ireland
  • The address of the registered office

This comes from the Companies Act and applies to emails as it does to letterhead. Limited liability partnerships have equivalent obligations. A sole trader trading under a name other than their own must give an address at which documents can be served.

If you are VAT registered, including the VAT number is conventional rather than required on email, but it saves your customers asking.

The three ways to do it

1. Everyone sets their own

How most businesses start and why the problem exists. It produces inconsistency immediately and drift permanently, and every change requires asking everybody to do something.

It has exactly one advantage: it costs nothing. For a business of three people that may genuinely be enough.

2. A transport rule in Exchange Online

A rule that appends a block of text or HTML to outbound mail as it leaves. Free, included with Microsoft 365, centrally controlled.

Three real drawbacks:

  • Senders cannot see it while composing, so people add their own as well and you get both.
  • Replies look wrong. The signature is appended to the very bottom of the whole thread rather than under what the person just wrote.
  • Personalisation is limited unless you are comfortable pulling attributes from directory fields, which then have to be accurate for every person.

Where it works well is as a minimal legal footer — company details only — with people keeping a short personal sign-off of their own. That combination is genuinely tidy.

3. A signature management product

Products such as Exclaimer and CodeTwo write the signature into Outlook itself, so senders see it as they type and replies behave correctly. They pull details from Entra ID and can run campaign banners if you want them.

Cost is typically £1 to £2 per user per month. For a business where email is the main customer channel, that is usually worth it. For a business of five people, probably not.

Choose the transport rule if you want compliance. Choose a signature product if you want consistency. Wanting both and paying for neither is how you end up with fourteen versions.

What to put on it

Short. Every element earns its place or comes off.

  • Name and job title
  • Company name
  • One phone number — the one you want people to use
  • Website
  • The legal details required above

What to leave off: multiple phone numbers nobody knows which to use, four social icons, an environmental plea about printing, a quotation, a banner image and the eight-line confidentiality disclaimer.

On disclaimers

The standard confidentiality paragraph has very little legal effect. You cannot impose obligations on somebody who received a message by mistake simply by asserting them at the bottom, and courts have been unimpressed by attempts to.

It persists by convention. If your sector expects it, keep it to two lines. If it is longer than the message it appends to, it is doing harm.

Practical points

Test on a phone. Signatures are designed on a wide screen and read on a narrow one. A three-column layout with a logo becomes an unreadable stack.

Keep images minimal. They are frequently blocked by default, they increase message size and a signature rendering as broken image icons looks worse than plain text.

Deal with mobile signatures. Nobody bothers, and the result is Sent from my iPhone on business correspondence. Either configure the mobile signature properly or use a transport rule that catches everything regardless of device.

Keep the directory accurate. If signatures pull from Entra ID, the job title field being wrong is now visible to every customer. That is a benefit — it forces the directory to be maintained — but it is a surprise the first time.

Do it once, properly

An hour to design, an hour to deploy, and it stays right afterwards. Compared with the accumulated cost of everybody maintaining their own badly, it is one of the better hours available.

If you would like signatures deployed centrally along with the rest of the tenancy configuration, that is standard work for our managed IT team. Get in touch.