please find the below workk which i have done with screen shots,
One thing, as I think you have two different quotes in the SOAPAction field. Please use these:
""
Instead of these:
””
Having said that, if it is a SOAP service, you might be able to build a library to consume it instead. Please see here:
It is a bit more complicated, as you would have to create a separate Library project to create a service out of your SOAP definition file, but could be useful if you have a lot of endpoints 
@loginerror,
no luck still same issue exist. even i am creating a new service from library and giving the endpoint then it was showing Invalid. see the below screen shot,
I think you might want to follow this tutorial on how to generate meta data for your SOAP requests:
shall i do the same thing in Salesforce application scope.
I think to get it working, I would (for now) forget about the library and maybe focus on making your POST http request work in Postman. Try it out
It will make it super easy to debug what is wrong with the particular request.
After you get it working in Postman, please share the working inputs from there and it will be easier to recreate it with HTTP Request in Studio
May i know PostMan activity available in studio. If yes let me know please.I couldn’t find.
It is a separate application that you have to download from their website:
https://www.getpostman.com/
i have tried and pass same parameters. Getting same issue over there.
soapenv:Body
soapenv:Fault
UNKNOWN_EXCEPTION
UNKNOWN_EXCEPTION: Premature end of file.
<sf:UnexpectedErrorFault xsi:type=“sf:UnexpectedErrorFault”>
sf:exceptionCodeUNKNOWN_EXCEPTION</sf:exceptionCode>
sf:exceptionMessagePremature end of file.</sf:exceptionMessage>
</sf:UnexpectedErrorFault>
</soapenv:Fault>
</soapenv:Body>
This means that you have to read the documentation for the endpoint you want to use and adjust your http request accordingly.
Without knowing specifics, it is impossible to answer what is wrong there, unfortunately 
getting 500 server error
@loginerror
Http Request unable to take headers which i am passing.
like
content type = “text/xml”
SoapAction = “”
But still issue exists in HTTP request activity. i am passing headers and parameters but it won’t pass. even in local panel i couldn’t see those headers and parameters values.
make sure issue needs to resolved otherwise no use.
i tried in the same way but no use. while debugging Headers not showing any values even if i am passing.
Issues with Headers only.
