The exporter recognizes special lines in the buffer which provide additional information. These lines may be put anywhere in the file. The whole set of lines can be inserted into the buffer with C-c C-e t.
#+TITLE: the title to be shown (default is the buffer name)
#+AUTHOR: the author (default taken from user-full-name)
#+DATE: a date, fixed, of a format string for format-time-string
#+EMAIL: his/her email address (default from user-mail-address)
#+DESCRIPTION: the page description, e.g. for the XHTML meta tag
#+KEYWORDS: the page keywords, e.g. for the XHTML meta tag
#+LANGUAGE: language for HTML, e.g. ‘en’ (org-export-default-language)
#+OPTIONS: H:2 num:t toc:t \n:nil @:t ::t |:t ^:t f:t TeX:t ...
#+LINK_UP: the ``up'' link of an exported page
#+LINK_HOME: the ``home'' link of an exported page
#+LATEX_HEADER: extra line(s) for the LaTeX header, like \usepackage{xyz}