IRS Form W-2 is a form used to report personal income. This form is generally completed by the employer and provided to the employee. The employee uses this form to submit personal tax information when filing with the IRS each year. The W-2 includes amount earned,tax amounts withheld as well as other amounts such as 401(k) contributions, insurance amounts, etc. These amounts are entered into an IRS form to determine tax liability for the respective year.