is it legal to elect not to withhold any federal taxes from my paycheck on W-4 2021?

[Steve_Smith]

Hello,

I would like to pay my taxes only one time when I file taxes. is it legal to elect not to withhold any federal taxes from my paycheck on W-4 2021?

what should I select on w-4 to do that?

Thanks

[SweetieJean]

The US tax system is a "pay as you go" one.   If you underpay throughout the year, you can be subject to interest and penalties.  When you sign your W-4, you say [u]nder penalties of perjury, I declare that this certificate, to the best of my knowledge and belief, is true, correct, and complete.

2021 Form W-4 (irs.gov)

Further, if the IRS determines that an employee does not have enough withholding, it will notify the employer to increase the amount of withholding tax by issuing a "lock-in" letter that specifies the withholding arrangement permitted for the employee. 

[DavidD66]

There is an option to claim exemption from withholding.  However, you may claim exemption from withholding for 2021 only if you meet both of the following conditions: you had no federal income tax liability in 2020 and you expect to have no federal income tax liability in 2021.