@taxpayerpa
You are confusing the HSA & HDHP terms ... to start with they are totally separate things and you can have one without the other. If you have a HDHP for a family that is HSA qualified then you can make HSA contributions to either your HSA, your spouse's HSA or a combination of both not to exceed the max allowed for the year.
The HDHP is your health insurance that simply has a qualifying high deductible. It is only good for one year and you pay premiums to have the coverage. It can cover self only or a family.
Now the HSA on the other hand is NOT insurance and it lives on until it is depleted ... it is a Health Savings Plan which is essentially an IRA for medical expenses since it mimics a traditional IRA and as such can only have ONE owner.
1) you make contributions pre tax
2) it can be invested and the earnings are tax free
3) all distributions are tax free IF you use them for qualifying medical expenses (better than IRA)
4) if you do not liquidate the account, when you turn 59.5 you have the option to roll it all into a traditional IRA you own (although I don't know why anyone would do so... https://www.thebalance.com/hsa-vs-ira-you-might-be-surprised-2388481)
5) you can make a one time transfer of IRA money into the HSA (actually a good idea...https://www.kiplinger.com/article/taxes/T027-C001-S003-tap-an-ira-tax-free-with-an-hsa-rollover.html)
