A Form 1099-K reports the gross amount of a payable transaction. You should receive a Form 1099-K from each payment settlement entity which you received payment. Entities, in this case, includes companies, individuals, and even states.
Example: Uber will send you a different 1099-K for each state in which you've completed trips. So if you have completed trips in both New York and New Jersey, you'll get a 1099-K for each set of fares.