Your business or yourself are hired to provide services to another company. A company can be a single person so that means that a wide group of people can ask for a W-9 form.
Most of the W-9 forms are given to independent contractors who are sole proprietors, and therefore self-employed people. Don't be surprised if a financial institution such as a bank will use a W-9 form to request your tax information. The second, third and fourth pages of the form are the instructions for you to use when you are looking for information about how to fill out the form.
In some cases it is a little more complicated so these instructions are useful.
The W9 Instructions for Requester is a set of instructions for the payer.
If you fail to furnish a correct TIN (Tax Identification Number) such as a social security number or a ITIN (Individual Tax Identification Number) the fine would be $50.00 unless there is reasonable cause and not willful neglect.
There is a $500.00 fine for false information as far as withholding is concerned or a false statement with no reasonable basis for the no backup withholding.
The Criminal Penalty Would be for falsifying information, such as certifications or affirmations. These can also cost you with fines and/or imprisonment.
Don't Misuse the TINs. The requester might be subject to civil and criminal penalties if they disclose or use TINs in violation of federal law.
Securely and with caution as you do not want someone else to get your information meaning your name, address and social security number, and then use that info to commit fraud such as opening a credit card in your name etc.
So the best way would be to hand deliver the W-9 to the person who is lawfully requesting it.
You could send it by the safest form of mail such as registered mail where it has to be signed for on receipt.
A less safe way would be to fax the form after you fill it out then sign and date it.