This article talks about how to install Ubuntu mate and Ubuntu Desktop on Raspberry Pi 4B
When I went to the Ubuntu official website to download the mirror image a few days ago, I saw that the Raspberry Pi 4B was added to the support list of Ubuntu mate, so I downloaded it and tried it out. It felt okay and smooth. Share the installation process here.
1. Go to the Raspberry Pi official website to download the image file. There are 32-bit and 64-bit image files. For the 4G version of the Raspberry Pi, you can choose either the 64-bit option or the 32-bit option, and the 2G version can choose the 32-bit option. Attached below is the link to
download the Ubuntu mate mirror image. After downloading, unzip the compressed file to get the .img file.
2. System programming.
We still use Win32DiskImager or Etcher. Both can 
use Win32DiskImager as an example. Choose the downloaded image file in one place, and choose the drive letter of the TF card in two places. Be careful not to choose the wrong one. If you choose your own USB flash drive, the files there will be gone. .
3. System initialization
This will not be described in detail here, just plug the card into the Raspberry Pi and start the system.
The installation of Ubuntu Desktop is the same as the installation of Ubuntu mate. It is very simple. Different operations are nothing more than downloading different mirrors. The download link of the Ubuntu Desktop system mirror file is attached below . The Ubuntu Desktop mirror download link is attached .
There is also a mirror image of the Ubuntu server in the link. Before installing the Ubuntu system desktop, you need to install the Ubuntu server first and then use sudo apt install ubuntu-desktop. The installation is very slow, and it is stuck when you start the desktop. The latest Ubuntu Desktop is Much better, a lot smoother.
Please correct me if the article is wrong!