how do i file my taxes without 1095-a

If you did not have health insurance from healthcare.gov and do not have a 1095A, then when the software asks if you have a 1095A you say NO to that, and move on.   You do not enter a 1095B or a 1095C, or anything about having Medicare or Medicaid.   

If you did, in fact, have marketplace health insurance then you must enter your 1095A.   To get the 1095A:

To enter your 1095A go to Federal>Deductions and Credits> Medical>Affordable Care Act (Form 1095A)

ENTER 1095A  TT FAQ

https://ttlc.intuit.com/turbotax-support/en-us/help-article/insurance-medical-benefits/enter-1095/L6CLFzhri_US_en_US?uid=m62itugr

TO FIND A 1095-A with healthcare.gov

How to find your 1095-A online

1. Log in to your account.
2. Under "Your Existing Applications," select your 2024 application — not your 2025 application.
3. Select “Tax Forms."
4. Download all 1095-As.

Get screen-by-screen directions, with pictures (PDF, 504 KB).