The requirements for ID Massachusetts may be found here.
I think that you are saying that in 2023 you were a part-year resident of Massachusetts and part-year resident of New Hampshire.
Taxable Social Security, taxable interest income and Vanguard investment income are likely not sourced to one state or the other like W-2 income would be reported in boxes 15 through 17 of the form.
If you lived in Massachusetts from January 1 through June 30 and in New Hampshire from July 1 through December 31, you may want to allocate 50% to Massachusetts and 50% to New Hampshire.
You may also identify other methods of allocation that would make sense given your situation.
What ever method is used, maintain a record of your calculations should one or another taxing authority have questions about the income reported.
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