If you had more than one employer and the total of box 4 (only box 4 not box 6) on all your 2018 W2s for Social Security is more than $7,960.80 you get the excess back on your tax return. And it is for each spouse separately, not combined. Check 1040 Schedule 5 line 72 for it. Then Schedule 5 goes to 1040 line 17.
Send the IRS copies of your W2 supporting the excess SS in box 4.
