For someone who is a novice to U.S tax preparation, one can wonder what is W-2? W-2 is a tax document that an employer provides in order to indicate the amount of payment made to the worker and the taxes withheld in the year. The W-2 document is not a tax form for contractors since it is usually connected to wages. While seeking for information about the document in Spanish language, one might come across the term w-2 formulario. The importance of knowing what should be found on your w-2 form lies in the fact that figures from this form will affect your annual tax return.