Can I Mark the Time Log as Billable and Add Notes in the Timesheet?

YES, you can mark the time log as billable and add notes to that in the timesheet. Please refer below steps to do so;

1. Navigate to Left Menu > Time Log > Weekly Timesheet
2. Hover on the time slot that you want to edit and click  icon (Refer Image 1)
3. Put the NOTE, select  mark as the billable hour & click Save (Refer Image 2)

                                                                                         (Image 1)

                                                                                              (Image 2)