Greetings, I (sole proprietor in retail business) recently had a request to do two custom frames for a client (which is another business - sole proprietor), and they want me to ship the completed work out of state to a third party. Once they agreed to use my company, they requested that I fill out a W-9 form and return it to them (W-9 is the form given to independent contractors by a business to request the Taxpayer ID # and Certification - I guess. Still pretty unclear about the form). I'm fairly new to the game, but have never gotten this request before, so I'm not sure what I should do. If I am supposed to fill out the W-9 form for them, what info do I give out to them? Not even sure what they want or need from me. Any advice would be greatly appreciated. Thanks!