The IRS W-9 form is required for workers who don't have taxes deducted from their pay. Consultants, self-employed workers and other independent contractors – not employees – must complete an IRS W-9 form to ensure their Taxpayer Identification Number (TIN) or Social Security number is accounted for when the client reports earnings to the IRS.

A W-9 requires the independent contractor to provide her tax classification, which usually is the business category. Independent contractors whose tax classification as a sole proprietorship must complete the W-9 just like businesses with other tax classifications, partnerships and limited liability companies. In general, corporations are not required to fill out a W-9.

Current IRS Tax Forms

To avoid problems, always use the most current tax forms. While tax forms generally don't have major changes from one year to the next, using the most recent version is wise.

For example, the IRS revised the latest W-9 in October 2018 as well as November 2017, and before that in December 2014. The person or company that requests your completed W-9 should provide you with an updated form; however, if you think you have an out-of-date form, access the latest version on the IRS website. Type "W-9" in the search box and download a PDF-format Form W-9.

If you're not using a fillable form or typing your information onto a hard copy W-9, print legibly with dark blue or black ink.

Line 1 of the W-9 requires you to enter the name you use on your income tax return. For a sole proprietor, this is your own name. In the second field – Line 2 – enter your business name if you're operating your sole proprietorship under a different name. For example, if you operate Doe's Candy as a sole proprietorship, enter your name on Line 1 and "Doe's Candy" on Line 2.

Line 3 is where you indicate your tax classification or business structure.

The first box is labeled, "Individual/sole proprietor of single-member LLC," and it's the box you check for your sole proprietorship business. You need check only one box for Line 3. Line 4 probably doesn't apply to you if your business is within the U.S. and if you're not exempt from backup withholding, but read the IRS instructions to determine whether you can claim the exemption.

Lines 5 and 6 require that you enter the address where your 1099 should be mailed. A 1099 is the form that details nonemployee wages – the amount of money you are paid subject to the Form W-9. Double-check that the address you have on file with the company or person who requests the W-9 is the same as on your W-9. If you move or change addresses, you will need to indicate that you're submitting a new address by writing "NEW" at the top of the form.

Part I: Taxpayer Identification Number

As a sole proprietor, you may use your personal Social Security number or an Employer Identification Number that you request from the IRS. Social Security numbers and EINs both contain nine digits, but they are in a slightly different format.

Part II: Certification

The IRS Form W-9 is an official form that requires your signature.

It also requires that you attest to the truthfulness of the information you provided, because if the information is false or constitutes fraud, you can be charged with perjury. Sign and date the form with an ink signature, or ask the requester if a digital signature is acceptable, if you're using a fillable form.

Protect Your Identity

Double-check your completed W-9 to ensure you correctly entered the proper information. Make a copy for your files, and send the completed, signed form to the requester.

When you transmit the signed document, consider sending it password-protected or encrypted so you don't risk having your Social Security number or TIN compromised.