Vendors don’t typically report your payments to them. It is the other way around. With Upwork, you are not required to issue a 1099, as you are paying a corporation and not the individual freelancer.
In order to report the expense, you simply add up all the payments you made to Upwork and call that computer or IT expense or, perhaps, professional or consulting fees. It is likely, you would have provided the same or similar services. If so, the total may include those other vendors.