My Samsung TV does not have the AppleTV+ app. Is there a way that I can install it?

Samsung say:

'The Apple TV app is available on select 2018, 2019, 2020, and 2021 Samsung smart TVs, Lifestyle TVs, QLED 4K and 8K TVs, and the Premiere projector. You do not even need to download it because it will appear in the Apps section on your TV.

Note: If the Apple TV or Apple Music app does not appear in apps, then it is not compatible with your TV.'

https://www.samsung.com/us/support/answer/ANS00082624/

More details from Apple (scroll down to Samsung): https://www.apple.com/apple-tv-app/devices/

If your TV isn't compatible you would need to buy a smart box such as one of the Roku models.

The Roku Express is $30/£30, or $40 /£40 for the 4K version.