The NJ COJ will not populate automatically, you have to enter everything from the W2.

Be aware the NJ wages box 16 might not equal Philly wages. Philly taxes everything and NJ defers 401k contributions but not 403b contributions. The amount to claim the credit might be lower than Philly wages; therefore the Philly tax withheld must be pro rated.

NJ also taxes the pre-tax medical, but the allows it to be added to other medical expenses on the NJ medical deduction worksheet.

pa NJ's tax credit law works for Philly wages tax but not PA. NJ's laws says "taxes paid to other jurisdictions." It doesn't say "paid to other states."

NJ and PA have a tax compact, which is why one state's employers do not withhold the other state's taxes.