Install claws-mail-bsfilter-plugin by entering the following commands in the terminal:
sudo apt update sudo apt install claws-mail-bsfilter-plugin
Spam filtering using bsfilter for Claws Mail
This plugin for Claws Mail allows filtering of spam messages using the Bayesian filtering program bsfilter. . The bsfilter can be trained with spam and ham messages to improve its spam detection capabilities.