TurboTax creates and completes the form 8889 based on your input.
Your input comes from code "W" in box 12 of your W-2 and any 1099-SA forms that you receive and enter into TurboTax.
Go to Federal Taxes->Deductions
& Credits->Medical and enter the "HSA MSA
contribution" interview. One of the first things that you are
asked for after saying that you have an HSA is the information from your
1099-SA.
The information in this section will populate form 8889, which is how
contributions to and distributions from your HSA are reported.
Please be sure to go all the way to the end of the HSA interview before exiting.