All users except collaborators can add tags. Tags help you organize items in Wrike outside of a basic structure.
Projects can be added as tags to any other task, folder, project, or space. The tagged item can be found in all of the projects it's tagged in.
Tasks, folders, and projects are automatically shared with the users who have access to the project where you tag them.
Navigate to the space containing the project you want to tag.
Click the project’s title to open its project info panel.
Under the title, the project tags are listed. Click + to add a tag. Hover over a tag and click x to remove it.