First, you need to enroll in AutoPay and paperless billing to receive the credit. After you enroll, you will receive the credit automatically on your bill. Credits will begin in 1-2 billing cycles after enrollment.
For AT&T Unlimited Starter, AT&T Unlimited Extra and AT&T Unlimited Premium℠ plans, your AutoPay and paperless billing credit is $10 per month for each phone line on your plan.
Credit cards, checking accounts, and debit cards can be used to qualify for the AutoPay credit.