Why didn't h.s.a contribution reduce taxable income

If your H.S.A. deduction was done through payroll, your wage income is already pre-tax. Your taxable wages (Form W-2, Box 1) are less your H.S.A. contributions so you aren't being taxed on your H.S.A. contributions when you enter your W-2 in TurboTax.

If you made an HSA contribution that wasn't reported on your my W-2, we'll ask about this uncommon situation when you step through the Medical section.

1. Look for the questions Were HSA contributions made in 2019? or Do you need to make any adjustments to your HSA contribution amount? 
2. When you answer Yes, we'll open a screen where you can enter your contribution. 

Related information: Where do I enter my HSA contribution?