To make sure that emails end up in the Spam folder, you can create a workflow Automator by navigating to  Admin > Automation & Productivity > Automation > Workflow Automator. Here are the steps to follow:

  1. Set the event to Ticket is Raised.
  2. In the conditions section, set the Subject or Description, contains (or Has any of these words) and provide the respective keywords you want to check for.
  3. If you wish to filter by a specific email address, ddd another condition as Requester fields.Requester email, is - provide the specific email address.
  4. In the actions section, select Mark ticket as Spam.

    Automatically move email containing a specific body or subject coming from a specific email address to spam

By following the above rule, emails containing the specified keywords will be marked as Spam.