A 1099-K form is similar to a 1099 form. It is to record specific payment types totaling more than $600 made to a US resident in any given tax year. The key difference between 1099-K, 1099 and 1099MISC is that 1099K is designed to cover payment card transactions or a third-party network transaction:
“Payment card transaction” means any transaction in which a payment card—or any account number or other identifying data associated with a payment card—is accepted as payment.
“Third-party network transaction” means any transaction settled through a third-party payment network—but only after the total exceeds the above thresholds.