For customer with a US Social Security number:
While most people sign up with US passports or US Driver's Licenses, we also accept signing up with a US Green Card. If you have a US Green Card please sign up using the Passport flow. We, unfortunately, do not accept signing up with a US military ID card or with a US Federal Employee Identification Card.
For customers without a US Social Security number:
If you have a passport, please sign up with that. If you do not have a passport but you have a national driver's license or ID card, please contact support to see whether your ID qualifies.