Is there a way to make the office plugin work without M-Files Desktop installed?

The Office add-in is part of M-Files Desktop so it's only possible to use by installing the desktop client.

Thank you.
I didn't think about that, but does that mean there is no way to use .docx templates with automated inserted properties while using the web?

Users can create new documents from templates also with the web client, however in that case the property values are filled when the document is checked in to the server. So the behavior is a bit different than with the desktop client where the properties are filled when the document is opened in Word.

For this to work you need to enable automatic updates for metadata fields.

OK thanks you! so only one of the user will need the desktop to create the template, and the others won't.

Yes, template authors need the desktop client to be able to add property placeholders but everyone can create documents from these templates also with other clients.