Install claws-mail by entering the following commands in the terminal:
sudo apt update sudo apt install claws-mail
Fast, lightweight and user-friendly GTK+2 based email client
Claws Mail is a powerful and full-featured mail client formerly called Sylpheed-Claws. It is also extensible using loadable plugins, which can provide support for additional features, like other storage formats, feed reader, calendar management, mail filtering, etc.