A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hi Angela,
From my understanding, you mean Add Attachment>File in a task in Planner by "link an Excel file". If so, that file can be edited by multiple users(members in that plan) at the same time. This is because that the files we attached to the tasks will be stored in the SharePoint document library associated with our plan automatically. Thus, the files can be accessed by the members in that Plan directly.
Regards,
Zixuan