Install dunst by entering the following commands in the terminal:
sudo apt update sudo apt install dunst
Dunst is a highly configurable and lightweight notification-daemon: The only thing it displays is a colored box with unformatted text. The whole notification specification (non-optional parts and the "body" capability) is supported as long as it fits into this look & feel. . Dunst is designed to fit nicely into minimalistic windowmanagers like dwm, but it should work on any Linux desktop.