How do i file my federal tax if my w-2 has a Ma. address but i lived in N.H. in 2018?

[mlgw]

I moved to Ma. in January of 2019 and lived in N.H. all of 2018 how shoud i file?

[DanielV01]

If you also worked in New Hampshire in 2018, it is likely that you do not have to file a state return at all.  New Hampshire does not have a state income tax on wages, (only on interest and dividends), and so you probably will not have to file a NH return.  And, while you may have a MA residency now, you were not a MA resident in 2018, so Massachusetts cannot tax your 2018 income.  (If you worked in Massachusetts, that's different.  You would have to file a MA nonresident return in that case.)

Next year, your income will be taxable to Massachusetts regardless because you live there.  New Hampshire's favorable tax treatment helps you this year, but will not prevent MA from taxing you next year.