SpamAssassin by default adds a number of headers to emails to help users, scripts, and email clients to effectively distinguish between spam and ham. SpamAssassin allows users and administrators to remove, redefine, or add existing headers.
SpamAssassin can also wrap spam in a report to hide the details of spam from the user, and provide a summary of the content instead.
In addition, SpamAssassin can also be configured to alter the Subject: email header to mark an email as spam. This is especially helpful when email clients do not provide the ability to sort and filter email by headers, but provide this ability for the email subject.
All email header and report definitions can be configured by editing the local.cf file for site-wide changes, or by editing user_prefs for changes that affect only one user.