Three things to be done:

1. Sign up onto odoo with your choice of gmail account you are using

2. install Odoo Plugin , by clicking on Get add-ons --> Google Workspace marketplace --> Odoo Inbox Addin Plugin

3. Configure the same to your Odoo App (Desktop App) post downloading. 

Your gmail account will be connected to Odoo Account.

Check this out: 
https://www.youtube.com/watch?v=E6cAjrgHdJo

Hope this helps. Cheers!