File exchange via webservice

there is an example that shows how to do

  1. a web project of a webService that receives files and can return files

  2. an example showing how to make a desktop project that sends and retrieves files to the webService (1)

I found documentation to iterate with the webservice but no documentation for file exchange, if anyone knows where to find an elucidating example, I ask if you kindly paste the link

Have a look at which has sample code for uploading a file to a web app.