From: http://a-pdf.com/faq/how-to-convert-ms-office-file-to-pdf-and-add-security.htm
There are three modes of A-PDF Office to PDF (http://www.a-pdf.com/office-to-pdf/index.htm) to choose. If you convert single MS Office file, Hot Directory Settings is better. Batch Convert can help you convert multiple Office files in minutes. If you know well Command line, then command line mode is more convenient.