Exporting to other script writing or word processing programs is a matter of saving a document in a different format.
A document exported from Screenwriter is designed to be an editable copy, not an exact duplicate. It will not have exactly the same margins, page breaks, or even number of pages as it does in Screenwriter. Neither will it have MOREs or CONTINUEDs. However, it will retain all of the text in your document and will be in general script format.