In the Timesheet settings, you now have the options to apply granular permissions to Timesheet references. These permissions you can then manage across different modules such as Expenses, Mileage and Time Tracking. In order to use Timesheet references in other modules you will need to enable the option in the settings for this module.
Administration > Company > Settings > Timesheets > Timesheets Settings
In this section you can give your Timesheet references labels and then set the permissions across the various modules on the system that support Timesheet references. Firstly, setting the Active tickbox determines whether it will appear in the module and Required will be whether it is a mandatory field or not.
See below a required and not required field on the Timesheet add screen.
In order to to add in the Timesheet references that are used on the system. You will need to populate these in
Administration > Company > Settings > Timesheets > Timesheets references