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.
If you get 2 W2 with different EIN for the employers then the above applies. If it is all on the same W2 with the same EIN employer then if you go over the $7,960.80 you have to get the excess back from the employer and get a corrected W2.
You pay Social Security on max wages of $128,400 for 2018. 2019 amounts might be a little higher.
