How to add parameters to WebHttpRequest GET call?

I am trying to make a simple REST GET call with WebHttpRequest and it fails. I have created a "Function App" in Azure which I can call and execute with an URL. Some part of the URL is a "Code" which I think makes the URL path unique. I also want to pass a search key like "ID=GG1234".
The URL looks like the following:

It works fine with Postman but I cannot make it work with Web Core. Postman sends the "Code" and the "ID" as parameters and I wish to do the same with WebHttpRequest but I cannot find where I can declare the parameters. I have tried to modify the example that follows with Web Core but the modified version does not work at all. I also have tried to send the URL as it is (like above) but it does not work.
Can you provide a better example code?
Please advise.

I would assume this is simply done by adding the request param as suffix to the URL used for TWebHTTPRequest?

I did that and it did not work.

Did you ensure that the parameters added to the URL are HTML encoded?
Given you want to add a key/value pair to the URL, this will do:

URL := '' + encodeURIComponent(Key) + '=' + encodeURIComponent(Value)