i'm trying to access my free 3-month subscription to Apple TV but it's saying I can only get a week free. How do I access the 3-month offer (having recently purchased a new iMac)?

This is copied from a previous posting (not mine)

Redeem 3 months free of Apple TV+ now.

You can start your 3 months free subscription to Apple TV+ after setting up your new Apple product. Here's how to redeem your offer:

•  Turn on your new Apple device and sign in with your Apple ID.
•  Open the Apple TV app. Make sure your device is running the latest version of iOS, iPadOS, tvOS, or macOS.
•  The offer should be presented immediately after launching the app. If not, go to the  Apple TV+ tabwhere you'll see the offer.
•  Tap Enjoy 3 Months Free.

Not trying to hijack the thread but I have the same issue, I received a new ipad pro 2 days ago, I am logged in with my apple id and when I go on the apple tv the only offer I get for apple tv+ is 7 days

Redeem the offer on your new eligible Apple device, not on a different device.

Verify that you meet the conditions: Apple TV+ offer - Apple

Read here is you have trouble redeeming: If you can't redeem your promotion for an Apple subscription - Apple Support

↳ Step 5 says to contact Apple about it if the other steps weren’t sufficient.

Me too. Can’t find my 3 months Apple TV offer