Installing Linux and WiFi support
I have tried to install Linux (Elementary OS) on both macOS and Windows; and number one impediment? -- the lack of WiFi.
Of course, there is an official troubleshooting here.
Immediate connection fix
If you cannot connect to the internet, how are you going to connect to the the internet to find out a solution?
- An Android phone
You can use "USB hotspot tethering" on Android phone to connect to the internet.
What to do when you now have a connection
Go to https://help.ubuntu.com/stable/ubuntu-help/net-wireless-troubleshooting.html.en and find out your WiFi driver, and install it.
Well, it depends on your hardware.
In my case, for Windows, it is Realtek RTL8821ce, and the solution on StackOverflow
How to install Wi-Fi driver for Realtek RTL8821CE on Ubuntu 18.04?
For macOS, it is the matter of activating proprietary Broadcom WiFi driver, and you just need an internet connection...