If you did not get a Form 1095-A, you do not have to include anything for the Marketplace insurance coverage as you enter your information on TurboTax.
There are some situations where returns get rejected because someone in your tax return is in the IRS database as having been covered by Marketplace insurance at some point during the year. If you do not have or did not think you needed Form 1095-A, please contact your state's Marketplace insurance to confirm whether anyone in your household was covered.
See the following link to find out more information about the Marketplace, and contact information for them:
The Federal government no longer imposes a penalty for not having insurance. If your state does, when you answer the question as to whether you had health insurance, and you answer NO, you can then select a WHY answer. If you say you couldn't afford it, that's all you have to do. I have a nephew that's been in that situation for several years (I do his taxes for him), and he has never had the return get rejected.