If your shared mailbox is in Microsoft 365 (M365), see Microsoft’s documentation on how to Create and add an email signature in Outlook on the web.
If your shared mailbox is still on-prem (i.e. Exchange Connect), follow the steps below.
Web browser access
In your web browser navigate to https://connect.uwaterloo.ca/owa/mailbox@uwaterloo.ca (change "mailbox" in the URL to be the generic username of the account.)
Log in with your own credentials: username@uwaterloo.ca, password, and Two-Factor authentication. (Note: Username is your 8-character username, e.g. j25rober)
Signature setup in browser
Click the gear icon to access Settings-- towards the upper-right of the page
Click Options from the drop-down list
Email Signature is found under Layout in the left navigation list
Check either or both of the boxes to include “my signature” on messages
Edit the text window, then click the Save icon above the Email Signature text window
Click Options at the upper-left to return to the mailbox view
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