Is this taxable income?
No. SSI is not taxable and does not get entered on a tax return.
WHAT IS THE DIFFERENCE BETWEEN SOCIAL SECURITY BENEFITS AND SSI?
https://www.ssa.gov/ssi/text-over-ussi.htm
No, SSI is not taxable income.
You don't need to enter your SSI benefits on the return. If you don't have another source of income, you are not required to file a tax return.