Create and add an email signature in Outlook on the web

Office for business Office 365 Small Business Outlook on the web for Exchange Server 2016

Create a signature for your email messages that you can add automatically to all outgoing messages or manually to specific ones.

Note: If the instructions don’t match what you see, you might be using an older version of Outlook on the web. Try the Instructions for classic Outlook on the web.

Create an email signature

  1. Sign in to Outlook on the web.
  2. Go to Settings Settings > View all Outlook settings > Compose and reply.
  3. Under Email signature, type your signature and use the available formatting options to change its appearance.Note: You can have only one signature per account.
    • If you want your signature to appear at the bottom of all new email messages that you compose, select the Automatically include my signature on new messages I compose check box.
    • If you want your signature to appear on messages that you forward or reply to, select the Automatically include my signature on messages I forward or reply to check box.
    • If you don’t select these options, you can manually add your signature to a selected message. For details, see Manually add your signature to a new message below.
  4. Select Save when you’re done.Note: You can always return to the Compose and reply page and select or clear the check box for automatically including your signature.

Manually add your signature to a new message

If you’ve created a signature, but didn’t choose to automatically add it to all outgoing messages, you can add it later when you write an email message.

  1. Go to your mailbox and choose New message.
  2. Type your message, and then choose More actions > Insert signature at the bottom of the compose pane.
  3. When your email message is ready, choose Send.

Ref: https://support.microsoft.com/en-us/office/create-and-add-an-email-signature-in-outlook-on-the-web-5ff9dcfd-d3f1-447b-b2e9-39f91b074ea3