Refer the decision tree in the attached image which may help you decide which format or formats to assign to users.

If multiple permission profiles with different Use Timesheet format options are assigned to a user, the Locked In-Out format takes precedence over other timesheet formats. For example, if the user is assigned an In-Out timesheet in one permission profile, and a Locked In-Out timesheets in another profile, they will be allowed to use the Locked In-Out format only.

If a user is assigned Standard and In-Out formats only, they can select which format they prefer to use, via their User Preferences.