FICA is Social Security and Medicare. They are on W2 boxes 4 & 6. Or if you are self employed you pay it on Schedule SE. You pay self employment tax on a Net Profit on Schedule C. Can you explain more? It’s not withholding, it’s a mandatory tax. Or are you paying a household employee?
If you are a W-2 employee your Social Security and Medicare was in boxes 4 and 6 of your W-2 and you just enter your W-2. If you are self-employed you will be paying self-employment tax for Social Security and Medicare.
I am not self-employed. My employer sent me a letter saying FICA tax withheld on my unvested stocks. It says "once you pay Social Security and Medicare thru this process, you'll no longer have to pay those taxes at vest. Your total expected pre-vest stocks withholding for 2024 is: XXX dollars".