While we don't have a way to track general clock in/out hours for employees, you can easily track time via Activity Log Entries in claims.
When updating a claim, you can choose to track the hours (and minutes) a person spends on a task.
Open the Update Claim wherever you see the blue up arrow related to a claim. The drop down menu in LOG ENTRY will have a spot for Billable Resource (you can select any assignable user in your company.) You can choose not to mark the task as 'billable' to your clients.
There are several reports that will extract non/billable time per resource (assignable users) and claims.