If you are an employee then you can only stop the federal or state taxes ... there is no way to stop the FICA taxes.
Now to do that you will have to fill in a new W-4 and there are no more "claiming dependents" like in the old days and you CANNOT claim exempt because you did have a tax liability on the 2020 return and will have one on the 2021 return.
Here is the new W-4 form with instructions ... https://www.irs.gov/pub/irs-pdf/fw4.pdf
If you don't pay the estimates and your withholding isn't any of the following you will be hit with underpayment penalties.
1) 2020 balance due after withholding is less than $1000
2) withholding covers 90% of 2020 tax
3) withholding is 100% (110% if 2019 adjusted gross income is over $150,000) of 2019 tax
