The high-level COM interface is the simplest way to add label printing capability to your application and should be considered the standard method to use. Using the high-level COM interface, you can print a label with as few as five lines of code (see the JavaScript and VBScript sample code for examples). If you want to print labels where the placement of the items (barcode, text, graphics, and so on) is constant, but their values change, then use the high-level COM interface. The low-level COM interface is useful if you need to do more complex operations, such as create, move and resize label objects dynamically within your application. With these added capabilities comes a great deal more complexity. The DLL interface is the most complex but the most powerful interface. It's unnecessary for an application that creates simple/basic labels. But if you plan on writing an application for custom label design and printing, then the DLL interface may suitable. The DDE interface is provided to support older applications that were developed in the past and should not be used going forward. All functionalities provided by the DDE interface are supported by the high-level COM interface.