You can request a csv export of users from the Survey Launcher. Note this is an Administrator function not available to other users.
To export users, login as an administrator, then click the "Users" (person) icon on the menu bar and go to the Search Users page. From there, specify any search criteria as specified here: Search for Users. Then click the "Export CSV" button. The Survey Launcher will create a csv file with the users matching the search criteria and then send an email to you with a link to download the export file.
Note that for security reasons, the link is only available for one hour.