Change format of IIS HTTP Error logging

Solution 1:

This list from Microsoft is a bit of outdated, as it does not include the recently introduced "streamid" field present in Windows Server 2016, but it definitely can help you specify the fields you need. https://docs.microsoft.com/en-us/windows/win32/http/error-logging-in-windows-server-2003-sp1

Solution 2:

Expanding on the earlier answer you need to assign a value to the following registry entry for chosen fields.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters] "ErrorLoggingFields"=dword:0fc884c7

Basically the value is a sum of all the bit values from the list below for whichever fields you want included.