If you want to restrict clock-in, but may have cases where employees need more flexibility with the distance, you can allow clocking in and out outside the set radius. The setting will apply to all users for the account.
Go to Dashboard > Settings > Time clock.
Scroll down and look for the Enable geofencing option. When it's turned on, you will also see the additional radius setting.
Any time an employee clocks in or out, their distance will then be marked on the timesheet report.