Your browser will either recognize the file type and immediately open the document or it will give you the option to "Open File" or "Save File." If you select "Open File," you will be prompted to select which program (Microsoft Word, Adobe Acrobat...) to open the file with. If you select "Save As," the file will be stored in a directory of your choice and will then need to be opened directly by navigating to the location to which it was saved.