Within Teamwork Spaces, you can delete a user via the site-level People area.
Note: Only site administrators can access the People area and manage users.
Click the three dots to the right of the relevant user and select Delete user.
This will open a confirmation modal where you can proceed with deleting the user.
Note: Deleting a user from your Spaces site will also remove them from any other Teamwork products you have enabled for the installation.
For more information, see: Working with the People Area