PeopleSoft

We have been working to integrate with a third party application.
We came across the API service which uses POST method with the request message format in x-www-form-urlencoded format.
We have referred to the documentation from Oracle Peoplesoft however, we are unable to get the clarity of which method/functions can be used to represent this format.
We are using the Non-Rowset message IB_GENERIC_REST for the request message.

We would like to have details of the configuration required and more importantly the code snippet that includes the information such as

Representing the request messages in x-www-form-urlencoded format. Lets say we have message elements such as client_id=test123, client_secret=test456, refresh_token=test789