View or change the properties for an Office file – Microsoft Support

In the Properties dialog box, click the tabs to select the properties that you want to view or update. Click OK. Any changes you made are saved automatically. Click the File tab again to return to your database. View or create custom properties for the current file. Custom properties are properties that you define for an Microsoft 365 document.

https://support.microsoft.com/en-us/office/view-or-change-the-properties-for-an-office-file-21d604c2-481e-4379-8e54-1dd4622c6b75