Within Teamwork.com, you can export users from your site to Microsoft Excel.
Click the More option in the main navigation menu and select People from the pop-out menu.
In the People area, go to the People subsection where you will see a list of all current users and contacts on your site.
Click the options button (three dots) to the top right of the People area and select Export to Excel from the dropdown menu.
For more information, see: Importing Users and Contacts