12 month free trial

In order to be eligible for that 12 month offer you would have had to purchase qualifying device, which not only includes Apple TV but also iPhone, iPad, iPod Touch and Mac. Once you claim the offer you would be able to view it on that device and if you had any other device that supports the TV app you would then be able to view it there. In case you weren't aware the TV app is also available on Smart TV's and other streaming devices. I have posted the page below.

Apple TV app - Devices - Apple (CA)

If you have a free subscription then that means you claimed it on a device from which you can use to view the subscription. It is also available on any other device that has the TV app. An Apple TV box is not required.

This is a user forum, no one here can access your account to cancel any subscription. If you no longer wish to use it then you need to cancel it. Be aware that you would not be eligible to receive another offer and cannot reactivate it should you change you’re mind.

https://support.apple.com/en-us/HT202039

If you have activated the free trial, then no, you do not need an Apple TV to watch it.

All the ways to watch Apple TV+ - Apple Support

To cancel:  view, change, or cancel your subscriptions

I have a follow up question to this thread: I received the same free 12 month subscription with my new iPhone. I logged into the app and set it up on my phone. When I turn on my Apple TV to use the app, it is asking for me to sign up for the free seven days. I do not want to sign up for that and cancel my 12 month free. What’s the work around on this?

Once you’ve claimed the offer on your phone it will be tied to your ID and would be available on your Apple TV (along with any other device that has the TV app) as long as you are using that same Apple ID.

Go into your account to ensure the subscription is still active. If that’s been verified and for some reason it isn’t letting you access on Apple TV then try logging out and back in, beyond that you may need to contact Apple.