Hi Pavan,
I am not sure what you are asking, but if you would like to know how to how to consume a REST service, I would like to suggest to have a look at the following page.
https://docs.mendix.com/howto/integration/consume-a-rest-service/
When using the REST consume action, you're able to set the HTTP-headers. Please keep in mind that you will need at least an endpoint in order to retrieve something.
Hopefully, this helps.