The plus (as in Applecare+) is something you pay extra for. This is offered in the Setup menu, and you have 60 days from the purchase date to signup.
Applecare covers non-accidental internal component failures, including a failed SSD and/or logic board.
If the damage was due to something like a liquid spill, you would pay $299 for "other damage", i.e. accidental damage. This is still better than the $400 to $1000 that a logic board replacement would cost without Applecare, and is extremely likely for something like a Mac Mini (more so with a laptop).
Data recovery is not included, so be sure to have a Time Machine set up.
I read that you can still get the $99 for 3 years if you go online, and there is an annual renewal available for $45 per year.
Now they show me 3.99/mo or 39.99 per year and call this AppleCare+ "single device plan". I select this, and select yearly coverage. Now it wants a payment method. It autofills with 933 N. Cherry (my old work address), which I change.
The fine print says the plan will automatically renew until cancelled. I can cancel in settings or using the Apple account login. They are showing my device as an AC+ Mac Studio (M5 Max/Ultra). I enter stuff for my credit card.
They say "cannot add payment method" and tell me to contact Apple Support. I call Apple Support, and they can't figure it out either.
I say the heck with this and go to the mini for the 3.99/mo price.
I tell Paypal to use the Costco CC.