If you are in a sort of business relationship or hire someone who is a US citizen or legal resident and who is an independent contractor, then you should get them to submit to you an IRS W-9 Form.
You are requesting their social security number or taxpayer identification number and certification.
When you hire a person and pay them $600.00 or more and they are self employed, then you will need a W-9 form filled out by them so that when you have to send them a 1099 form stating their earnings from you in the year their address and social security number or TIN (Tax Identification Number) is correct.
As it does not need to go to the government unless there is an audit etc.
The person who got paid otherwise referred to as the payee or the signer has to sign the form.
The signature certifies that the info on the form is correct. It also assures that the signor is a US citizen or resident alien or some other person from the US. They also could be the representative of a corporation, a company, or a partnership.
That is the fine for each time a person who has paid you the money or a partner has asked you to fill out a W9 Form and you refuse. There are civil and criminal penalties for your misuse of the form as far as false information, etc. So don't play around with it but rather do a good job. It is very simple for the most part.
It does have options but most often you would be required to simply put in your name, address, check the box for sole proprietor and add your social-security number. Then sign it and date it.
You can actually be imprisoned as well as fined. An example is if you create a W-9 form statement that is not true and gets you into a "no backup withholding situation", and you are not exempt from the backup withholding requirement, the $500.00 penalty can be implemented..