Make sure that you're eligible
To see if the promotional trial is still current, visit apple.com/promo. Most offers are available for only a limited time. To make sure that the device or subscription that you purchased qualifies for the offer, read the terms and conditions.
If your offer isn't listed, it might have come from another company. Contact that company for help with redeeming the offer.
Check if you or a family member already redeemed the offer
If you or a family member already redeemed the offer, you can't redeem it again.
Update the software on your device
Update to the latest version of iOS or iPadOS, macOS, watchOS, or tvOS. Then try to redeem the promotion again.
Sign in on the eligible device
To redeem some promotions, you need to sign in with your Apple ID on the eligible device. Then try to redeem the promotion again.
If your eligible device is a Mac and you've just set it up, you might need to wait at least 4 hours for the offer to appear.
Contact Apple Support
If you tried these steps and you still can't redeem the offer, contact Apple Support.