PostgreSQL has four primary documentation formats:
Plain text, for pre-installation information
HTML, for on-line browsing and reference
PDF or Postscript, for printing
man pages, for quick reference.
Additionally, a number of plain-text README files can be found throughout the PostgreSQL source tree, documenting various implementation issues.
HTML documentation and man pages are part of a standard distribution and are installed by default. PDF and Postscript format documentation is available separately for download.