One option is the Path to Pennie, which is a form you can file with your Pennsylvania state income tax return which will open a special election period for you. For more information, look here.

For the Path to Pennie form REV 1882, click here.

This is a form that you file with your Pennsylvania income tax. If you have already filed your taxes, you can simply file an amended return without changing any information but including Form REV 1882. If you use tax software like Turbotax, there may be an option to include this form. I believe that towards the end of the questions regarding your state taxes it will ask you about whether you need health insurance.

Once you have filed, you do not need to wait for the state to process your return or amended return. You can simply call Pennie at 1-844-844-8040 and attest that you have submitted the form along with your tax return and they will immediately open a special enrollment period for you.