WPF application with rest requests and proxy concerns

I am writing a WPF app for Windows - C#. It will do some Rest requests to a server I have publicly available.

This application will be delivered to external clients.Do I have to consider proxy implications from their side when they are running my application?

If so I don't find that much info out there about designing your code around this issue. I am worried that I am over complicating the issue by using things like HttpClient and HttpClientHandler etc. and then having to wrap all this stuff with a UI and further complicate my application.

What should my approach be, and does anyone know of any good online tutorial that can explain this stuff simply.