How do I amend my taxes from 2017? I was penalized for not having health insurance and I did have health insurance.

See this TurboTax support FAQ for amending a 2017 tax return originally completed and filed using TurboTax - https://ttlc.intuit.com/community/amending/help/how-do-i-amend-a-return-in-turbotax/01/27372

If you still have access to TurboTax 2017 file an amended return and mail back with the letter you received from them. If you have a form 1095-C or one of the other forms, you might be able to get away with making a copy of it and sending it in with the letter they sent you. I would advise sending certified to prevent further penalties and interest.