UnifySig

Guide · Gmail

How to add an email signature in Gmail

Gmail makes signatures easy to add and easy to get wrong. The editor accepts pasted rich text and keeps most of it, but it silently drops images that are not hosted on the web. Here is the full set-up, the defaults most people miss, and the fix for the missing logo.

Updated 30 September 2026

Questions

Why did Gmail remove the formatting when I pasted?
Can I use an HTML file as a Gmail signature?
How big can a Gmail signature be?
  • Guide · Outlook

    How to add an email signature in Outlook

    Steps for new Outlook, Outlook on the web, classic Outlook, Outlook for Mac and the mobile apps, plus fixes for images, spacing and replies.

  • Guide · HTML

    HTML email signature best practices

    The rules that keep an HTML signature rendering the same in Outlook, Gmail, Apple Mail and on phones: tables, inline styles, hosted images, fonts and size.

  • Guide · Apple Mail

    How to add an email signature in Apple Mail

    Add an HTML signature with a logo to Mail on a Mac, what the iPhone and iPad apps can and cannot do, and fixes for the font, image and iCloud sync problems.

  • Guide · Mobile

    How to set up an email signature on your phone

    Where the signature setting is in the Outlook app, the Gmail app, Mail on iPhone and Samsung Email, what each can show, and how to get one signature everywhere.

  • Guide · Thunderbird

    How to add an email signature in Thunderbird

    Paste HTML source or attach a file, set it per identity, keep the logo showing, and fix the dashes, reply placement and missing signature on replies.

  • Guide · Yahoo Mail

    How to add an email signature in Yahoo Mail

    Turn on and paste a signature in Yahoo Mail on the web, set one in the Yahoo Mail app, and fix logos that vanish and formatting the editor drops.

  • Guide · Proton Mail

    How to add an email signature in Proton Mail

    Set a formatted signature in Proton Mail on the web and a mobile one in the apps, add a logo by link, and what changes on the free plan or with Bridge.

  • Guide · Zoho Mail

    How to add an email signature in Zoho Mail

    Create a signature in Zoho Mail, attach it to an address, choose where it sits on replies, upload a logo, and what admins can and cannot set for everyone.

  • Guide · iCloud Mail

    How to add an email signature in iCloud Mail

    Set a signature for iCloud Mail on icloud.com, what the web editor keeps, and how to get a formatted signature with a logo on a Mac, iPhone or iPad instead.

Rolling this out to everyone?

UnifySig applies one signature policy to every mailbox in Microsoft 365 and Google Workspace, with names and titles from your directory. Leave your email and we will tell you when it launches.

One email when UnifySig is fully launched. No drip campaign, no sales calls.