1. Navigate to Users → All Users.
2. Hover over Bulk actions, and click on Suspend users (available in the Learning Center plan or higher).
3. Prepare your .xls file. Each Bulk action option offers a template excel file. You can download it, add the data and re-upload it. The template file contains 1 column: email.
4. Add a Name for Users Actions log, to identify the progress of your Bulk action.
5. Click on Suspend users.
To find the record of your Bulk actions, navigate to Report Center → Users Action Log.
You can find more about Users Action Log here.