Please see this answer from BMcCalpin:
Form 8889 reports on your HSA (Health Savings Account) contributions and distributions. It is generated automatically by TurboTax based on answers in the HSA interview and on your W-2, and attached to your 1040 tax return.
If you have a code of W in box 12 on your W-2, then you have an HSA and must add form 8889 to your return.
Even if you do not, but have a 1099-SA, then you should do this by going to Federal->Deductions & Credits->Medical->HSA, MSA Contributions, and completing the interview. Be sure to go to the very end, to where you are returned to "Your Tax Breaks".
Line 2: HSA contributions you made for 2020 (or those made on your behalf), including those made from January 1, 2021, through April 15, 2021, that were for 2020. Do not include employer contributions, contributions through a cafeteria plan, or rollovers. You will be asked your contribution amount.
Employer contributions made to your HSAs for 2020: This is on your W-2.
