Gmail aliases enable you to send and reply to emails from one "main" Gmail account on behalf of an "Alias" account that is assigned from Google Workspace.
For example, here at Go Mail Merge we take advantage of Gmail's Alias feature by being to send emails from our support, privacy, and sales accounts all from the same Gmail account.
Open up Gmail then click on the settings gear icon then select see all settings
Select the "Accounts" tab at the top of the settings bar
Click the "Add another email address" Link
Finally enter your other Google Workspace email address that is part of your domain
And that's it! You can now both send and receive emails as an alternative Google Workspace email address which enables you to be more organized and appear more professional when working with others.