Hi,
I have a query:
I am planning to live in NJ but work in NY with a company incorporated in NJ.

1. What state taxes will I pay?
2. I have heard that both states will deduct personal income tax
3. Do I have to tell my employer something in advance to help reduce double taxation.

There's no reson for your company to withhold NJ tax, since you will be working in NY and hence will owe NY non-resident tax on your wages. The NY tax rates are higher than NJ, so it is doubtful that you will owe NJ anything. I suggest you talk to your employer and verify that they will deduct NY tax, and not NJ.

I work in ny but live in pa do I still have to file in but states for state income tax

i work in ny but live in pa do i still have to file in but states for state income tax

Yes, you will have to file a NY non-resident tax return and also a PA resident return. You take a credit on your PA taxes for taxes paid to other jurisdictions (namely NY), so that aren't taxed by two different states on the same income.