Your system may be configured to allow overtime work to be recorded separately from normal time. Synergist has up to two categories for overtime, which your system administrator can label as required ("weekends", "evenings" etc).
Choose which overtime entry fields to allow in company settings > timesheets tab. You can also edit the labels that appear in the entry interfaces here.
If overtime is enabled in a company all users will see the overtime entry fields by default:
However, you can choose to hide these overtime input fields user by user if they are not appropriate for use by all timesheet users. These options are on the access tab of a user record:
"Normal", "Overtime1" and "Overtime2" are the default labels, they may have been re-named for the timesheet entry interface, but for setting theses options they will always appear as the defaults.