For both postpaid and prepaid accounts with Sprint:
1. Account Number: Look for a 9 - digit number in the upper center of your bill.Additionally, you can find it on your online account page.
2. Passcode / PIN:
When calling customer service, use your 'call-in' code as the passcode.This is typically a PIN.
,You can create or alter your PIN on the account page if needed.
If you're unable to access your online account:
3. Contact Sprint: Call Sprint at 1 - 888 - 211 - 4727 for assistance.
By following these steps, you should be able to locate your account number and manage your passcode / PIN for both postpaid and prepaid accounts with Sprint.