A W9 form is an Internal Revenue Service (IRS) document. It is used by companies and clients that hire independent freelancers and contractors. This form is not filed with the government. Earnings by employees are not recorded on the W9. The form is designed to collect data on independent contractors, such as name, contact information, taxpayer identification or social security number. The IRS permits you to create and use a substitute W9 form if the document is essentially the same as the agency's W9 form. You can get additional details on by checking the government's W9 instructions. Companies and clients use the data on the W9, or its allowable substitute, to generate a Form 1099. This form documents the earnings the client paid to its independent freelancers and contractors during that particular tax year. The issuer of the 1099 is required to send the form to the IRS and the contractor. Some states receive a copy for independent contractors working in their jurisdictions. Unlike the W4, the W9 does not authorize automatic withholdings for social security or other tax payments. Independent contractors are liable for the taxes assessed on their earned income. Contractors are usually required to make quarterly payments on their estimated taxes to the IRS and submit a Form 1040-ES. Consult your tax professional to determine whether your state also mandates quarterly payments. U.S. citizens and resident aliens working as independent contractors must have W9s. Foreign national contactors are required to complete a W8. Like the W4 the W9 must be signed, but the signature does not require witnesses. Freelancers normally complete the document or a copy of the original to the client or company. The IRS requires that you must have a W9 if payments to a freelancer exceed $600 in one year. You are not required to collect the information or maintain the form if the freelancer's compensation is less than that amount. You can download the W9 and instructions from the IRS website.