WordPress provides the ability to split long entries into multiple pages. The advantage of this is increase in page view related ad impressions. It also makes up for easier scrolling and better reading experience for long text based posts. However, splitting the content to frequently and unnecessarily can be detrimental to user experience.

To split the post into multiple pages, use the following tag, while in text mode (the tag will not work in visual editor):

<!-- nextpage -->

This should work in most well coded themes.

If the nextpage tag does nothing you should check if your loop contains the wp_link_pages template tag:

<?php wp_link_pages(); ?>

Inserting the wp_link_pages template tag into single.php file will make the nextpage work in your posts. Inserting it to page.php will enable you to divide your static pages as well.