Libreoffice official website provides some fonts for download
1. Download fonts on Libreoffice official website
Official website address: https://zh-cn.libreoffice.org/download/fonts/ . Find the font you need and download it to the Ubuntu local.
2. Unzip the downloaded zip file
You can directly use the visual interface and right click to decompress. You can also use the command line to decompress, the command is as follows:
$ unzip SourceHanSerifCN.zip
3. Copy the unzipped folder to /usr/share/fonts/
$ sudo cp -r SourceHanSerifCN /usr/share/fonts/
4. Go to the /usr/share/fonts/ directory and update the font cache
$ cd /usr/share/fonts/
$ fc-cache -fv
5. Restart Libreoffice to see the newly added fonts