NtSetInformationTransaction - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTTMAPI_H
#if (PHNT_VERSION >= PHNT_VISTA)

NTSYSCALLAPI
NTSTATUS
NTAPI
NtSetInformationTransaction(
    _In_ HANDLE TransactionHandle,
    _In_ TRANSACTION_INFORMATION_CLASS TransactionInformationClass,
    _In_reads_bytes_(TransactionInformationLength) PVOID TransactionInformation,
    _In_ ULONG TransactionInformationLength
    );

#endif
#endif

View code on GitHub
#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwSetInformationTransaction(
    _In_ HANDLE TransactionHandle,
    _In_ TRANSACTION_INFORMATION_CLASS TransactionInformationClass,
    _In_reads_bytes_(TransactionInformationLength) PVOID TransactionInformation,
    _In_ ULONG TransactionInformationLength
    );

#endif

View code on GitHub

This function is documented in Windows Driver Kit here and here.