Form 1099-K is closely tied to Schedule C, thus in TaxSlayer ProWeb by virtue of creating a Schedule C you will also see Form 1099-K paper clipped to the left side menu that shows forms that have been completed in the return.
In ProWeb, there's no Form 1099-K entry menu similar to Form 1099-MISC or 1099-NEC, so it's not available to print with the return along with other source documents, nor listed in the Fees Setup menu in Configuration to be assigned a fee. Its presence in the left side menu is only due to its close association with Schedule C.