How to called this internal async task directly from postmen tool in ASP.net

net mvc code .cs file

  namespace Service.class
    {
        public class ServiceHelper
            {
                internal async Task<Jobject> ProductMaster ()
                    {
                        try{
                            return await task.Run()
                            }
                        Catch 
                            {}
                    }

I want to call this method directly From URL and fetch that JSON data or from the "postman" tool.

For e.g can I put a URL like abc.com/api/ProductMaster on the URL or in Postman fetch result?

Any way to do it. Please help me