Hello there, @MeMyselfandI1012.
Correcting your previously filed W2 and 941 forms is my top priority. However, to ensure that there's a need to increase the FIT taxable wages, I suggest consulting your accountant. They can lead and provide info on the best thing you'll need to do.
If you don't have one, we can help you find someone to help you. You may use our Find an Accountant tool to locate accountants based in the US.
Once everything is verified, here are some helpful articles for your guidance in amending your form:
You may also generate a payroll summary report to see your payroll totals, including employee taxes and contributions.
Feel free to let me know if you have further questions or concerns. You can always reach out to the Community or me anytime you need a helping hand. Take care!