The booklet feature prints two pages on each side of the paper. The print driver reorders the pages and orients them so they are in numerical order when folded. The pages then can be stapled to create a booklet. Remember that the layout of a booklet differs from the layout of a document with one page image on each side of the paper. Line wrapping and page breaks vary accordingly.
Use Booklet to format your document to print as a booklet. If your document is already formatted as a booklet in the application used to create it, do not select Booklet. Instead, use printing options on the Printing Options tab, under the Finishing menu.