How can I transfer a file via POST and Powershell?

Hello

I have to upload a file via POST (HTTP) to a webserver and download it via Powershell.
The Download with the command "System.Net.WebClient" works great, but I don't know how I can implement the File Upload via Powershell.
Do I have to use cURL or is there another way to make a File Upload via Post and Powershell?

Thanks for your help!