In order to require a worker to select "cost code" after tagging a project you'll need to make sure the following settings have been toggled on for any "project time" group where you want this requirement enabled.
To get to this setting follow these steps:
Login into Workyard
Click on the "Gear" icon then click "Company"
Select "Project Time"
Make sure your "Project Time" settings match the following settings for any groups that require a worker to select a "cost code" when tagging a project