I am creating a sharepoint site in which I have a separate group that only contributes by adding documents to the library. But creating a contribute permission group is allowing the user to edit the web part. Also, I created a separate permission level so that the users cannot edit web part but then it is not allowing users to add documents. It is displaying access denied message.
How can prevent particular group of users from editing the web part but also allow users to add documents to the library or lists?