When all else fails, read the instructions:
Who must file?
Any PA resident, nonresident or part-year resident
• Received total PA gross taxable income in
excess of $33 during the tax year, even if no
tax is due; and/or
• Incurred a loss from any transaction as an
individual, sole proprietor, partner in a partnership or PA S corporation shareholder
There is no Philly return to file for wages. But you might be able to file a wage tax refund petition if some of the wages were paid for days worked outside Philly. Or sick or vacation days, too.
Then you have to adjust the COJ if 100% of Philly wages should not have been taxed by Philly.
IF the employer did it right, there should be no PA income tax because of the reciprocity compact. No PA return is needed for this job, except to get refunded PA income tax improperly withheld.
NJ resident, in-Philadelphia employee, needs to file NJ COJ to claim credit against NJ tax. Be aware that Philly wages are usually higher than NJ wages, so you might not claim 100% of wage tax as a credit.
IE, city taxes 401k deferral while NJ does not, so city wages are higher than NJ wages.