1. Install ibus

sudo apt-get install ibus ibus-clutter ibus-gtk ibus-gtk3 ibus-qt4
im-config -s ibus
sudo apt-get install ibus-pinyin

2. Set language support

Open Language Support, choose Keyboard input method system to IBUS, and Apply System-Wide.

3. Reference

• Ubuntu20.04安装中文输入法_走走逛逛的专栏-CSDN博客_ubuntu20中文输入法