Company-Wide Email Signatures in Microsoft 365 and Google

What a Singapore company email signature should include

Section 144 of the Companies Act 1967 requires a company's name, in legible romanised letters, on all business letters, statements of account, invoices, official notices and publications, and since 2004 its registration number as well, as ACRA's Practice Direction No. 1 of 2004 explains. The Act does not name email specifically, but business emails do the job of letters, so including both in every signature or footer is the safe approach.

For a limited liability partnership, ACRA's page on publication of LLP name and UEN says invoices and official correspondence must show the LLP name, UEN and a statement that it is registered with limited liability.

Central footer vs per-user signature: which to use

Both approaches have trade-offs. Many small firms combine them: a per-user signature for the personal details, and a central footer for the legal line that must never be missing.

Third-party signature tools sit in between: they manage per-user signatures centrally. They are useful for larger teams or frequent rebrands, but they add a subscription and another app with access to your mail.

Microsoft 365: add a company footer with a mail flow rule

Microsoft's guide to organisation-wide disclaimers and signatures in Exchange Online describes the method: a mail flow rule (transport rule) that adds HTML or plain text to the top or bottom of messages. The text can use tokens such as %%DisplayName%%, %%Title%% and %%Phone%%, filled from each user's directory profile.

1. 1

   Fill in user details in the admin centre

   Check each user's display name, job title and phone in the Microsoft 365 admin centre, because the tokens pull from there.

2. 2

   Open the Exchange admin centre mail flow rules

   Go to Mail flow, then Rules, and add a rule to apply disclaimers.

3. 3

   Scope it to external recipients

   Apply the rule when the recipient is outside the organisation, so internal emails stay clean.

4. 4

   Write the footer HTML

   Use simple HTML with your company name, UEN and the tokens. Link a small hosted logo with an IMG tag if you want one.

5. 5

   Add an exception to avoid repeats

   Except if the body already contains a unique phrase from your footer, so long reply chains do not stack footers.

6. 6

   Choose the fallback and test

   Pick what happens if the footer cannot be added, such as an encrypted message. Send test emails to an outside address.

Microsoft warns not to use the Wrap fallback on rules that affect incoming external mail, as it interferes with Safe Attachments scanning; this footer rule only applies to outgoing mail.

Google Workspace: use the Append footer setting

Google's help article on adding a standard footer to outgoing emails covers the Append footer setting. It applies to everyone in an organisational unit, including messages sent from aliases.

• In the Admin console, go to Apps, Google Workspace, Gmail, then Compliance
• Select the organisational unit, then configure Append footer
• Write the footer text with the company name and UEN; add formatting if you need it
• Images must come from a public web URL; images stored in Google Drive cannot be used
• Optionally tick the box to add the footer to internal messages too
• Changes can take up to 24 hours; test by emailing an address outside your domain

Personal signatures in Gmail are set by each user in Settings. Admins who want to set them for everyone can use the Gmail API, which Google documents under managing aliases and signatures, or a signature management tool.

Signatures on phones and in replies

Outlook and Gmail mobile apps have their own signature setting, and the default is often 'Sent from my iPhone' or 'Get Outlook for Android'. Ask staff to set a short text version in each app: name, title, company name and phone. The central footer still adds the legal line.

Keep reply signatures short. Some teams set a full signature on new emails and a one-line version on replies, which Outlook supports as separate defaults.

Images, logos and spam filters

Image-heavy signatures cause problems: attached images appear as mystery attachments, some apps block remote images by default, and a large image with little text is a classic spam pattern. A few simple habits avoid all three.

Deliverability depends far more on SPF, DKIM and DMARC than on the signature. If emails are landing in spam, start with our guide to SPF, DKIM and DMARC. If you want your logo shown next to emails in Gmail, see BIMI.

Do it yourself or get help?

Setting a central footer is a 20-minute admin job in either platform, and a good DIY task. Per-user signatures take longer only because someone has to check every person's desktop and phone. If you are still setting up mailboxes, our guides to setting up business email and aliases vs new mailboxes cover the basics.

If you want it done as part of a proper set-up, our Business Email Setup (S$249) creates Microsoft 365 or Google Workspace mailboxes for up to five people on your own account, with MX, SPF, DKIM and DMARC records and an email signature template included.