Before you can file your federal income tax return, you've got to have in hand all of the necessary documents.

This includes not only your Form 1040EZ, 1040A or 1040 that you'll send to the Internal Revenue Service, but also the various statements regarding your wages, investment earnings and tax-deductible interest paid on certain loans. These documents come from varying sources -- your employer, bank, investment accounts -- and aren't always in the same format, but they will contain the same information.

In addition to ending up in your mailbox, copies of these statements go to the IRS and, when applicable, to your state tax agency. So make sure you have these documents, that they are correct and that that you transfer the information accurately. You can be sure that tax examiners will take a close look at their copies to make sure that those numbers match up with what you enter on your return.

Here are three common statements that many taxpayers need to complete their tax returns:

Form W-2, Wage and Tax Statement
This form comes from your employer or its payroll processing firm and details the payments you've received. And it's not sent only to you. Your employer prepares multiple copies of your Form W-2:

• Copy A is sent to the Social Security Administration.
• Copy B is sent to the employee, to be attached to the federal income tax return.
• Copy C is sent to the employee, for personal records.
• Copy D is held by the employer, for business records.
• Copy 1 goes, if applicable, to the taxpayer's state, city or local tax department.
• Copy 2, goes to the employee who then uses it when filing local or state tax returns.

Form W-2 is critical because of the information it contains -- it is, after all, called an income tax. Your return is incomplete without it.

Your Form W-2 contains vital information, including:

The W-2 box and what it indicates If you're using Form 1040EZ If you're using Form 1040A If you're using Form 1040 1. Wages, tips, other compensation Your total wages are entered on line 1. Your total wages are entered on line 7. Your total wages are entered on line 7. 2. Federal income tax withheld Your total federal tax withheld is entered on line 7. Your total federal tax withheld is entered on line 39. Your total federal tax withheld is entered on line 64. 9. Advance Earned Income Credit payment You can't use this form. Your payment is entered on line 37. Your payment is entered on line 61.

Employers are required by law to get W-2 forms to their employees by the end of each January. That means you should get them by early to mid-February. If you don't, contact your employer. If you ask and still don't have your W-2 by Feb. 15, contact the IRS. The agency will request the form from your employer. If you still can't get your W-2, as a last resort you can use IRS Form 4852, Substitute for Form W-2, Wage and Tax Statement, to recreate your earnings statement from your last pay stub.