Input files for PWscf codes may be either written by hand or produced via the PWgui graphical interface by Anton Kokalj, included in the QUANTUM ESPRESSO distribution. See PWgui-x.y.z/INSTALL (where x.y.z is the version number) for more info on PWgui, or GUI/README if you are using SVN sources.
You may take the examples distributed with QUANTUM ESPRESSO as templates for writing your own input files: see Sec.2.6. In the following, whenever we mention "Example N", we refer to those. Input files are those in the results/ subdirectories, with names ending with .in (they will appear after you have run the examples).