I was offered 3 months free and Apple wants to charge me?

1. Apple offers an extended free trial to Apple TV+ to new subscribers that recently purchased a new qualifying Apple product (iPhone, iPad, Mac, Apple TV box). See terms and conditions. This offer would need to be redeemed on the new qualifying Apple product in the Apple TV app; not on a different device. If this applies, what is your qualifying Apple product purchase?
2. Select partnering companies may also offer free trials to Apple TV+ in combination with a purchase of a product or service from them. These offers may have different durations. These offers would have their own terms and conditions. These offers would have their own redeem procedures. If this applies, which company made you an offer?
3. The offer isn’t automatically applied. Users have to complete a redeem procedure as described.
4. After signup, users get a confirmation email with all the subscription details, including length of the trial, and first billing date after the trial, if still subscribed by then.

For the offer from Apple: —

Read here how to redeem: Apple TV+ offer - Apple

Read here about the conditions: Apple TV+ offer - Terms and conditions - Apple

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

↳ Step 5 says to contact Apple if the prior steps didn’t bring a solution. They can assist.

Note that for new Macs, users have to additionally sign in to the TV app (menu Account), for the redeem option to appear.

An Apple TV+ subscription gives you full access to all of the Apple TV+ catalog, but not other content in the Apple TV app. Buy/rent movies from the iTunes Store will have to be paid for separately. The third party channels in the Apple TV app will have to be paid for separately.