
Hi @ALGOURDIN Erwan ,
Welcome to our forum!
Are you referring to the add-in in my image below?
According to my search, your templates are stored within your mailbox, so they are also available to you when you are using another computer or Outlook on the Web.
See: My Templates Office Web-Add-in (Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
Hope that may help you.
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