You can add description to Timesheets in the week view by double-clicking on a cell as shown in the screenshot below. In the popup, go to the description section and add details there.
If you add description regularly, then you can add the description column to the timesheet. Here's how to do that:
- Go To My time
- Click on the Gear icon
- Click on Customize My Timesheets
- In the popup, go to the Week View section
- Check the show description in grid box
You will now see a description column added to the timesheet.