For every edit (including adding a manual time entry and deleting a time entry), you will need to input the reason for doing so before you can confirm the edit or deletion.
To view the reason for the change and the change itself, go to:
On the web, the "Change History" section below the member's personal detailed timesheet.
On mobile, it's a reverse clock icon in the top right corner of the member's daily timesheet.
In this list you can see changes from a particular member:
Any edits on the time entry, including regular and overtime hours (by admin/managers only)
Any time entry deletion
When the time entry was manually added
Your members can only edit their own time entries and are not allowed to edit anyone else's. If you want to restrict your members from editing their time entries, you can disable it under the Restriction section of the Time Tracking settings.