If an employee was hired prior to 2020 and has not completed a W-4 since, their Federal Income Tax withholding may be based on the Pre-2020 W-4 format, which was based on filing status and exemptions.
The IRS advises that the employee provide a new W-4 form when they experience a life event to ensure accurate tax calculations. Any W-4 completed after 2020 uses the current W-4 format, which includes additional factors. The W-4 form and FAQs can be found on the IRS website.
(Continue in State Income Tax)