Joining a program
If your company has been invited to a program, you'll get an email with a link. Open it, verify your phone number, and you're in. Invited businesses skip the approval queue.
If you're joining on your own, the host company will have a sign-up page you can apply from, or a form on their website. Applications go to their staff to approve, which usually takes a day or two.
Either way, the next two steps are the same: sign your W-9 so the program can pay you, then add the crew who'll be sending referrals.
What you'll need
Your business details as they appear on your tax filings: legal business name, address, and tax ID. The W-9 is signed electronically in the app; there's nothing to print or mail.