When you worked you had withholding from the job but now you have 2 sources of income and not enough being withheld ... so you can have some withholding from the SS benefits (there are 4 options for that on the W-4V) or increase the pension withholding by adding an amount to line 4C of the W-4 P ...
https://www.irs.gov/pub/irs-pdf/fw4p.pdf
https://www.ssa.gov/manage-benefits/request-withhold-taxes
SS benefits are up to 85% taxable depending on your other income and filing status.
Social security only becomes taxable when added to sufficient other income. If you are otherwise required to file a tax return, you do need to enter it in Turbotax (TT). TT will determine the taxable portion.
Social security (including SSDI) becomes taxable when your income, including 1/2 your social security, reaches:
Married Filing Jointly(MFJ): $32,000
Single or head of household: $25,000
Married Filing Separately and lived with your spouse at any time during the tax year: $0
