Form 8889 is generated by TurboTax when the taxpayer has contributions to or withdrawals from an HSA. The “T“ means that the form is for the taxpayer, the first-named or top-named person on the tax return. If the HSA was owned by the spouse, TurboTax would refer to form 8889-S.
You don’t normally need any information from this year‘s form 8889 to fill out this year‘s tax return, the form is prepared by TurboTax for you. Line 18 refers to the “last month rule“, this would apply if you did two things.
1. contributed to an HSA last year using the last month rule to calculate your eligible contributions, AND,
2. You had an interruption in your HDHP coverage this year, which causes contributions made using last month rule to be invalid and result in a penalty.
if you maintained HTHP coverage for all of 2020, then you have made a mistake in the program someplace when it asked you what kind of health insurance you had. If your spouse was covered by a family HDHP all year, then you should also indicate that you were covered by a family HDHP all year, even though you were not the owner of the policy. If your spouse was covered by a self policy, make sure that his answers are correct and then he indicated he was covered all year.
If your spouse did have a break in HDHP coverage and was not eligible to contribute to an HSA for all of 2020, then you need to use the instructions for form 8889 to answer the line 18 question. You have to determine how much of your 2019 contributions are retroactively ineligible.
