Install kmail by entering the following commands in the terminal:
sudo apt update sudo apt install kmail
Description:
full featured graphical email client
KMail supports multiple accounts, mail filtering and email encryption. The program let you configure your workflow and it has good integration into KDE (Plasma Desktop) but is also useable with other Desktop Envionments.
Homepage: http://kontact.kde.org/kmail/
Version: 4:17.12.3-0ubuntu1
Section: universe/mail