Locking (Hiding) A Project
You can lock a Projects project to make the project accessible to certain users and not others. The project will be invisible to those who do not have permission, with the exception of Administrators, who always have permission.
To lock a project, hover the cursor over the name of the project in the Task List, click the three vertical dots (⋮) to the right and choose Edit Project from the drop down list. Click the Locked checkbox and then click Save Changes.
On the next screen, select the users or groups that should have permission to access this project. Click the Continue button. You will be returned to the Task List, and you will see a red lock symbol to the right of the locked project.