what should have been done
since you're saying she got 2 w-2's you needed to enter 2 w-2's
first her federal return
based on her state of domicile being PA all her income is included on her PA return ( state of domicile means where her permanent residence is located)
she also has to file a NY return for the income earned there. this is prepared first because she files as a non-resident
then you prepare the PA return and get a credit for some or all of the taxes paid to NY, if any.
not sure she should have filed as an independent with only $1200 in income. did she provide over 1/2 of her support in 2020? support would include college costs and the costs of living her living at home. if she did not she can not file as "independent". Then her federal return should have indicated she could be claimed as a dependent on another's return. This is true even if the other taxpayer entitled to claim her as a dependent did not.
one other criterion has to be met for her to be a dependent - qualifying child:
If not a full-time student (parts of 5 months during the year), under 19 at the end of 2020. If a full-time student under 24 at end of 2020
