Free One Year Subscription for Appletv on new apple device

The offer is still available. See this guide: Apple TV+ - One Year Offer - Apple

• Your free year of Apple TV+ is included when you buy a new iPhone, iPad, iPod touch, Apple TV, or Mac from Apple or an Apple-authorized reseller.
• You redeem the offer on your new device in the Apple TV app. Follow the four steps in the guide.
• The offer is for the first registered user of the new device, by Apple ID account.
• You and your Apple ID account must be in a country or region where the Apple TV+ service is available.

If you qualify, and if you did as described in the guide, and you still do not get to see the year offer, then contact Apple Support. They can assist in getting you the service, if needed using activation codes.