Actually, you don't
need to mail in Pennsylvania's Form 8453, or anything else.
Pennsylvania has a
very odd Form 8453 requirement, as compared to other states. You'll simply need to for your parents to sign the form and keep
it for their records for three years. You
do not actually send the form anywhere.
Please see the
instructions after the first two pages of PA-8453,
2018 PENNSYLVANIA INDIVIDUAL INCOME TAX DECLARATION FOR ELECTRONIC FILING
for more information.
