If you own an LG TV and bought that TV in the last few years (2018 onwards), you should be eligible for 3 months free AppleTV. The caveat being that you must not already be an AppleTV subscriber.
The promotion runs until 31st January. The following are some terms that are on LG's website:
This promotion is available in countries where Apple TV+ is available. It applies to 4K and 8K LG Smart TVs release form 2018 to 2022, and is available to new Apple TV+ subscribers from 1st December 2022 to 31st January 2023.*
Click below to go through to the LG page.
If you open your LG TV apps menu and look for 'LG Content Store', you should be able to see the offer and can click through to activate it.