Open a new email in Outlook
As a reminder, your add-in is only accessible from the new email composition page. Open your Outlook and click on "New Email."
In the top ribbon, you will find your Add-in.
If you cannot find your Add-in, you can refer to this article.
Pin your Add-in
Open your add-in, then click on the pin at the top of the add-in.
Once done, your add-in will remain open and will appear every time you open a new email. This will allow you to select your different signatures quickly, without wasting time.
Feel free to contact support if needed.