This article is for cPanel Accounts. Determine where your account is with this guide.
SpamAssassin is a free program that comes with all cPanel and WHM installations. It's used to filter out incoming email on a server side basis. Meaning it's sorted through as it comes into the server. If this is available to a user, they are able to activate or deactivate it from this section.
There is also a SpamAssassin Spam Box that can be enabled also. Meaning that all email that Spam Assassin deems as spam, will be forwarded to this box and can be viewed by the user at a later date.
To activate Spam Assassin, click on "Spam Assassin" from the Main Mail Menu. Click on "Enable Spam Box" and "Enable Spam Assassin". To deactivate Spam Assassin go to the same place, once it is enabled and click both buttons to disable.