If you need to track some additional parameters on your time logs, you can set up to three custom fields in the Time logs options section of Account admin:

The custom fields that are set up by the administrator are shown for all team members of the account on the Track page:

To show data from custom fields in your Detailed view and report, make sure to select the correct columns with the 'Settings' button:

The values for custom fields can be entered in numbers only.