If your return has been fully processed, then you need to do an amended return to add your SS benefits.  If your original return has not been fully processed, you need to wait.  The IRS may contact you about the missing SS benefits.  Since SS benefits are taxed I don't think it would increase your refund, unless you had taxes taken out, then maybe but it depends what tax bracket the new income puts you in.

To amend your return:  If you used TurboTax Online, simply log in to your account and select “Amend a return that was filed and accepted.” If you used our CD/download product, sign back into your return and select “Amend a filed return.” You must file a separate Form 1040-X for each tax return you are amending.

Where do I enter an SSA-1099, SSA-1099-SM, or SSA-1099-R-OP1?

https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/enter-ssa-1099-ssa-1099-sm-ssa-1099-r-op1/L0EWrnsaW_US_en_US

You do need to amend your tax return to add the Social Security benefits. The SS may be taxable depending on the other income that is included in your return. But you should add this to your return to find out how much if any is taxed.

Whether or not your Social Security income is taxable depends on your total income, including your Social Security plus any other income.

Your benefits may be taxable if the total of (1) one-half of your benefits, plus (2) all of your other income, including tax-exempt interest, is greater than the base amount for your filing status. The taxable portion of the benefits that are included in your income and used to calculate your income tax liability depends on the total amount of your income and benefits for the taxable year. You report the taxable portion of your social security benefits on line 6b of Form 1040 or Form 1040-SR.

Please see this from the IRS for more information.

@arthur42 

@arthur42  Do not amend your return until your original return has been fully processed.  The IRS gets copies of those forms, they may send you a letter asking for the information.

To amend your return:  If you used TurboTax Online, simply log in to your account and select “Amend a return that was filed and accepted.” If you used our CD/download product, sign back into your return and select “Amend a filed return.” You must file a separate Form 1040-X for each tax return you are amending.

Where do I enter an SSA-1099, SSA-1099-SM, or SSA-1099-R-OP1?

https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/enter-ssa-1099-...