W-4 definition and meaning
A W-4 tax form is an IRS document that every new employee completes. It is used to determine what taxes should be withheld from their pay by a new employer.
More about W-4 tax forms
Last revised in 2020, the current W-4 uses a five-step process for determining employee withholding. Not only should it be filled out when an employee is hired, but also any time their life or financial situation changes.