Install claws-mail-doc by entering the following commands in the terminal:
sudo apt update sudo apt install claws-mail-doc
Description:
User documentation for Claws Mail mailer
This package provides the Claws Mail user's manual. The document is available in text and HTML formats for screen reading, and also PostScript and PDF formats for printing.
Homepage: http://www.claws-mail.org
Version: 3.16.0-1
Section: universe/mail