Suppose a HTTP request from LB is forwarded to service A. Now service A calls service B, B calls C and so on..
Is it possible to embed the actual request params, data, etc automatically(configurable from control plane) when services communicate with each other?
Your application services need to do it themselves.
This is similar to the way headers need to be forwarded between services if you want to tie the automatically generated Zipkin trace spans together to generate a full distributed trace: https://istio.io/docs/tasks/telemetry/distributed-tracing.html.
Another example is in the Bookinfo sample. The services (e.g., productpage) forward to upstream services (e.g., reviews) the user cookie that is used to control routing for a test user in the example tasks.