Subscription

You will have to add a payment method in order to be able to subscribe, but the first charge for it will happen after the free trial (if you are still subscribed by then).

the subscription is only for the appletv+ material as in produced by apple it does not give you free access to all the third party material that apples itunes store hosts

if you want to know more Apple TV+ - Apple

But you can watch on your TVs right?

After sign-up, during the free trial, users can watch the subscription content on all their devices with the Apple TV app.