Do corporations complete or file a w9 form.
Go to the IRS' website and search for the w9 form in PDF format.
http://www.multimap.com/maps/?hloc=GB|w9%202he#map=51.52329,-0.19308|16|4&loc=GB:51.52329:-0.19308:16|w9%202he|W9%202HE
The best place to download a W9 form would be your local Tax website. They will have the most recent form for you to download. There are some other website, but to keep it safe you shouldn't download it there.
Yes, as long as you keep making the payments.
Do you mean how long does a broker / Bank keep them on file after application? or do you mean how long is the application good for consideration?
one year
About a year until you file taxes
Hold on to it for as long as possible.
As long as your customer is an active customer.
Hold on to it for as long as possible.
For 3 years.