I moved from TX to PA this year. Do I need to file form with my employer or ask them to withhold more for state income tax?

[xmasbaby0]

By "this year" do you mean you moved in 2025?   If you are living and working in PA then you became subject to PA state income tax when you began to live and work in PA.   If your employer is not withholding PA tax from your paychecks, you need to have that changed or you will owe PA at tax time.

MOVED OR NEED TO FILE PART-YEAR STATE

https://ttlc.intuit.com/questions/1901560-how-do-i-file-if-i-moved-to-a-different-state-last-year

https://ttlc.intuit.com/turbotax-support/en-us/help-article/printers-printing/file-part-year-state-r...

https://ttlc.intuit.com/turbotax-support/en-us/help-article/printers-printing/file-part-year-state-r...

ALLOCATE PART YEAR

https://ttlc.intuit.com/turbotax-support/en-us/help-article/state-taxes/allocate-split-income-part-y...

[rjs]

If your employer cannot withhold Pennsylvania tax you should make estimated tax payments to Pennsylvania so that you do not end up with a big payment due, plus penalties, on your Pennsylvania state tax return at the end of the year.

[NCperson]

@piuskweon note also, you will not pay tax on the income earned while working and living in TX.... PA will just tax the money you earned once living in PA.   You'll want to file a Part Year PA tax return for 2025 so that the TX income is excluded.