Where to start learning servers?

Question

Programming

Hello.
I program for Android, but I have always written only local applications. And the moment came when I needed to develop an application that interacts with the server, which I have to write. The problem is that I have no idea how to do it or even what to google.
Therefore, I ask you to answer simple questions:

1. Where to get a server?
   
2. As I understand it, something needs to be uploaded to an empty server so that it can run code in a certain language and process requests. What exactly needs to be filled in and how to set it up?
   
3. What language would you recommend for the backend?
   

Thanks in advance.

Answer 1

1. Buy a VPS
2. The selected OS is already installed on the server. You need to install the required languages.
3. Python, Go.

Answer 2

Google JSON API or Restful.
A PHP server is started on any hosting or Node / Python on a VPS.
If you write in Java, then in principle you can use it.

Answer 3

you can use firebase as baas

Answer 4

Install virtual machines (ubuntu for example) using virtual box
for php backend