Within Teamwork, you can mark a project as complete at any time via the project options menu.
While viewing the project, click the options button (three dots) to the right of the project name. In the Manage Project section of the project options menu, click More Options and select Complete.
You can also access the project options menu when viewing groups of projects in other areas of your site such as the projects list or chart views.
You can also mark a project as complete in the area where you set the project start and end dates.
Note: Marking a project as complete does not restrict the ability to make changes to the project. To prevent further changes, you would need to archive the project.
For more information, see: Completed Projects