I have only ever used the HTTP object for JSON webservice requests.
For this the following were set:
Address URL: was set the the URL of the JSON web service address
Body: was the JSON text content
Content Type: was set to ""application/json""
Method was set to ""POST""
I am no code expert, but It looks like the Blue Prism HTTP object simply exposes the .NET System..Net.HttpWebRequest functionality, so to know better how to use it your best bet might be to head over to MSDN.