How do I add my "Free 3 months Apple TV" to my existing Apple TV account?

Hi lvtees,

We'd like to share some helpful information regarding promotions. To begin, you will want to look over If you can't redeem your promotion for an Apple subscription which will cover the eligibility and steps to go through. You do mention having an existing subscription, which would also cover this. We hope these details help and provide the clarification needed.

Thanks for using Apple Support Communities.