Nextcloud collaborative tags for specific file extension like docx, xlsx

Hello Team,

I am new to Nextcloud and wondering how can i tag for specific file extensions such as .docx, .xlsx, .odt, etc., to implement the retention policy for a specific group of users, though i have followed the provided nextcloud admin document.

my observation i can tag files and folders regardless of extensions (a particular type of file) and it works as expected, but however i am unable to figure out how to tag specific mime type of file.

hence requesting to Nextcloud experts to enlighten me to perform this.

Thanks for your support in this matter.