1. Open the employee's timesheet detail page and click + Add Timecard.
2. Set the Date, the Clock-in → Clock-out times and the Role.
3. Optionally click Add Break under Unpaid Breaks or Paid Breaks, pick the Rule and the break's Start / End times.
4. Click Save Timecard.

This records hours even when the employee had no shift scheduled. The hourly rate is taken from the employee's roles at that moment. Requires the Edit Employees Timesheets permission and the Human Resources module.