If you use Clockwork to track work you do on behalf of clients, Clockwork Pro allows you to include a checkbox on your worklogs to indicate whether or not the work performed is billable.
Use the dropdown menu to enable the billable worklogs. This means that when worklogs are created, there will be a Billable checkbox on every worklog. If you are not using Clockwork to track hours that you will bill, simply disable the feature.
In Clockwork Pro worklogs also include a Tags field which can be used to record the type of activity performed, the cost center, clients, or any other relevant information you want to include on your timesheets/reports.
Tags work like Jira labels field in that users can select more than one tag and can create tags on the fly. However, you also have the option of creating a limited list of tags in your Clockwork configuration: