First, you'll need to set up a few aspects of your account so that the necessary info shows up on the super bill. CLICK HERE to see how.
If billing is on:
Start by billing your client for a session. You can do this in the Unbilled Session section of the Session Billing page.
Once a client has been charged, go to the Session Billing page and view Billed Sessions.
Next to the session you just billed, you'll see "Billing info/Receipt."
Click the Receipt link and the new super bill receipt will be downloaded.
The client you billed automatically has access to this super bill in the Session Payments section of their own portal.