Welcome to Apigee Community 🙂
Apigee Trace window allows you only simple GET calls, but it intercepts any API call made to proxy & displays in trace window for debugging purpose.
You can use Generic API Console / any other http client tool like postman, curl to make a call to your proxy & see API details in trace window. Keep us posted if you have any queries.
We cannot "add" any parameter in the trace window.You can add filters on the requests captured in the trace window