You need to provide a W-9 to anyone who pays you and then you in turn will get a W-9 from those you pay. The W-9 is information only ... the paying company uses that info to issue a form 1099-nec (used to be 1099-misc) next January. And if you have subs of your own that you pay then before you give them a single penny you need to have them fill in a W-9 so you have the info needed yourself next January. Nothing worse than paying someone and later have to track them down and beg for that info.
https://www.irs.gov/pub/irs-pdf/fw9.pdf
