Step 1:  Click on the Account icon in the top right. 



Step 2:  From the dropdown, select 'Account Settings.'



Step 3:  Select 'Default Settings' from the menu on the left and adjust the desired 'Watermark Settings.' Click 'Close.'




Note: This will be applied to all future uploaded files, not existing files in the account. If you do not edit a user's name, the system will default to what is in front of the @ symbol in the user's email address.