Do you have a long post content and feels like it is better to split then into two page, its just two simple step:
In HTML mode add the text <!–nextpage–> where you want to break the page.
If Step 1 does not work for you then you need to check your single.php in your theme folder and locate if wp_link_pages() is there and if not add it.
'before' => '<p><strong>Pages: </strong> ',
'after' => '</p>',
'next_or_number' => 'number')
Let me know if you are not able to make it work, shall help you fix it.