PageReference pdf = Page.PrintSet;
  pdf.getParameters().put('id',customerId);
  pdf.setRedirect(true);

  // Take the PDF contents
        
  Blob b = pdf.getContent();

  // Create the email attachment
  Messaging.EmailFileAttachment efa = new Messaging.EmailFileAttachment();
  efa.setFileName('actionPlan.pdf');
  efa.setBody(b);

  email.setFileAttachments(new Messaging.EmailFileAttachment[] {efa});