Hello Excel gurus!

I have office 365, and my team uses a lot of shared documents, however, we need to limit edits to only the original user. I tried using the "protect worksheet" option, however, other users were still able to edit the document. Why would this be happening? They should need the password to make any edits, but even without the password, they were able to edit the excel file.

Any advice on what to try?

Thank you in advance!
Liz