Are you using Windows 10? This is probably the most flexible but also the most expensive solution but Adobe Acrobat is of course the standard when it comes down to creating, editing and managing pdf-file. Adobe Acrobat comes with a dedicated Outlook add-in which lets you convert a single message or selected messages to a pdf-file, append an already existing pdf-file or convert an entire folder at once. There are also many options available to set the compatibility, whether or not to include the attachments in the pdf-file and configure security, encryption and password settings. Another option is to automatically convert your new messages to pdf-files for archiving purposes on a set interval. Besides a dedicated Outlook PDF add-in, it also comes with a PDF printer which lets you create pdf-files from any other application as well. View: Adobe Acrobat.