Three tax forms with similar-sounding names cause more confusion than almost anything else in the U.S. tax system, but each one serves a completely different purpose and applies to a different point in the year. * A W-4 comes first, chronologically: you fill it out when you start a new job, and it tells your employer how much federal income tax to withhold from each paycheck. You can update your W-4 anytime your situation changes — getting married, having a child, taking a second job — and the changes to your withholding take effect going forward, not retroactively. * A W-2 comes at the end of the year: your employer fills it out, not you, summarizing the actual wages you earned and the actual taxes withheld throughout the year, based on what your W-4 instructed. Employers are required to send W-2s to both employees and the IRS by January 31 each year, and you use it to file your tax return. * A 1099, specifically 1099-NEC for most independent work, is a completely different animal — it's for freelancers and contractors, not employees. If a business pays you as a contractor rather than an employee, they issue a 1099-NEC reporting what they paid you, but they don't withhold any taxes from that payment at all. * That last difference has real financial consequences: W-2 employees have taxes taken out gradually with each paycheck, while 1099 contractors are responsible for setting aside and paying their own estimated taxes throughout the year — usually quarterly — since nobody is withholding anything on their behalf.