When I replace my computer, what happens to the apps such as Norton that are subscribed to on the old computer?

After going for two months with just a little tablet, I now have a terrifying new computer.*

How do I transfer subscription things like Norton and Acrobat to the new computer?

How do I stop automatic billing on the old computer (if, say, I’m switching from Norton to McAfee)?

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*It’s just a modest HP laptop, but any new box of tech is terrifying to me.