If the admin deletes a user the user will be moved to the deleted user list, the user cannot login to the app with his existing credentials and he cannot again sign up with the same email or password. But if the admin restores the user from the deleted user list the user will be able to log in using his previous credentials.
To restore a user from deleted user list click on deleted user list under users management. Click on the restore button next to the user account which is to be restored.
Admin Page → Users → Deleted Users List → Restore
1. Click Deleted User List
2. Click Restore
3. User Restored