What printers do you have? How many? What models? Do you want your empty cartridges to be refilled? If you want new cartridges, do you want original manufacturer, or equivalent cheaper off-brand?
I would imagine that different companies have various procedures. Some might have a detailed form to fill out, and some might require nothing more than a note saying "Hey, Bob -- we're out of toner." Why don't you ask your store purchase officer what they require?