Can’t sign to Apple TV on Samsung tv

Can’t sign to Apple TV on Samsung tv

What is the exact message that you get? The issue is probably not in the password itself.

should I reset my password?

No. That should only be done for security reasons.

If I do that does it change all the things I need the password for

Yes. A changed Apple ID password applies to every use of that account and its sign-in uses.

You have to use your AppleID password to log in. Also, I believe you are referring to Apple TV+ which resides inside the Apple TV app if you have a 2018 or later qualifying Samsung TV.