A W-4 is the Employee's Withholding Certificate that you give to your employer so that your employer can withhold the correct federal income tax from your pay.
IRS Form W-4 - https://www.irs.gov/pub/irs-pdf/fw4.pdf
IRS website for the tax withholding estimator - https://www.irs.gov/individuals/tax-withholding-estimator
However, if you were referring to the Form W-2 that you receive from your employer which shows your total income received, federal tax withheld plus Social Security and Medicate taxes withheld then that form will be provided by the employer no later than January 31, 2021 for tax year 2020.
