I am trying to use the WordPress pages but WordPress is overwriting certain characters.
the '>' character is turned into '& gt;'
why is WordPress changing these characters? is it possible to turn character conversion off for certain pages?
What you are doing is incredibly dangerous. You can break your site horribly, or have your entire server hacked. With a PHP in content plugin there is nothing stopping an editor from copy pasting a PHP shell in to the content editor and taking full control of your site.
If you have content on a page and want to include custom code, you should use one of the following:
There are many alternatives, all well documented and with hundreds of questions asking how to do them from new developers on this site alone. I encourage you to ask!!
You should NEVER use plugins that let you put PHP code inside your posts. If I were to do this, I would face immediate dismissal from my job. I urge you to consider alternatives.