During export, you can include the content of another file. For example, to include your .emacs file, you could use:
#+INCLUDE: "~/.emacs" src emacs-lisp
The optional second and third parameter are the markup (‘quote’,
‘example’, or ‘src’), and, if the markup is ‘src’, the
language for formatting the contents. The markup is optional, if it is not
given, the text will be assumed to be in Org mode format and will be
processed normally. The include line will also allow additional keyword
parameters :prefix1 and :prefix to specify prefixes for the
first line and for each following line. For example, to include a file as an
item, use
#+INCLUDE: "~/snippets/xx" :prefix1 " + " :prefix " "