There are two ways in which work can be recorded as billable or non-billable.
In the case of projects where certain project are non-billable, you can use option to enable or disable "Billable" when configuring the task. To do this, locate the task from the Tasks page, and edit the details. Untick the "Billable" field for the task.
If you have project in which some work may be billable but other work for the same task may be non-billable, we recommend creating a separate rate code to record the time. Hence you should have 2 rate codes, one to use for billable work and another to use for non-billable work. The rate code can be set up with a unique description that appears in the timesheet, so it is easy for the user to identify. Rate codes can be created from the Rate Codes page (from the Settings menu). Once you have created your two rate codes, ensure that your project have both rate codes applied to them. This can be done by editing the details of the task (either by clicking on the edit icon for the task or when creating a new task). The rate codes appear on the right hand side of the task details. Once you have done this, you can then make use of the Rates Management features to set charge rates for the billable rate code, but leave the charge rates blank for the non-billable rate code. You can apply these charge rates per project or per task (or even set it as a default rate for your employees). Further information on setting up charge and pay rates can be found on the Rates Management help page.