SpamAssassin can add information to emails to aid users (or email clients) to identify and process them as spam or ham. It can add lines to the email message header and change the subject of an email to include a tag noting that it is spam. SpamAssassin can also create a report on an email, with explanatory text and a list of all spam rules that the email triggered. This report is particularly useful to prevent members of staff or customers from viewing potentially offensive content. They can see a summary, and open the attachment if they choose. SpamAssassin can also add a report if it detects web bugs in an email.
This chapter describes the customization of the headers and reports generated by SpamAssassin.