As of December 5, 2019, the IRS provided their final draft of the new W-4 form for the year 2020. Any new employee hired within 2020 or existing employees making an edit to their W-4 should be filling out the new form. Existing employees who do not need to make edits, are not required to update their form to the 2020 version. This new version has 3 additional sections (steps 2,3, and 4) that help employees select accurate tax calculations. These sections are optional and should be filled out by the employee if applicable.
Please reference this IRS document for instructions on how to fill out the form. If you still need assistance filling out the form, please reach out to a tax advisor in order to determine how to proceed for your situation.