People over 65 years old use Medicare, a government program.
About 27 million are uninsured. For the most part, this means they don't want health insurance because if they can't afford it the government will buy it for them. You can debate what is affordable.
The rest generally buy private insurance, either by paying out of their own pocket or by sharing the cost with an employer.
And of course if you have the money you can just pay for healthcare out of your pocket.
And of course if you are young and healthy you might not consume healthcare at all. I went for decades without paying for any healthcare except may a few dentist visits.
I think a lot of the time/effort/talk/discussion/arguments/etc is just political rhetoric.