This guide is for IT administrators who want to roll out MyDesk Outlook Addin to either specific individuals or the entire company.
1. In admin center > Settings > Integrated apps:
You can also use the link below:
Microsoft 365 Administration
2. Click on user integrated apps:

3. Insert the following URL: https://outlookaddin.mydesk.io/manifest.prod.xml

4. If this is intended to be a test or you just want to roll out the MyDesk Addin to specific people, insert them here:

5. Click save and the MyDesk addin will be deployed within a few hours.
(Note: Sometimes it can take up to 24 hours)