If you had insurance all year and it was not Obamacare, for the federal taxes, you do not need to "prove" anything. You will just enter that you had insurance all year by doing the following after fully logging into your return:
- Click Federal
- Click Health Insurance
- Select You had insurance all year or I'll pick and choose which months
- Click Continue
- You will get a message saying that is all we need
If you had Obamacare insurance and you are getting a penalty, this may not be a penalty. It may be a repayment of the Advanced Premium Tax Credit if you received too much based on your final income on your return.