This is a great tip for any app, like Notes, Pages or Mail, that you type into using the iPad's virtual keyboard. Rather than having to go to the second screen of the keyboard every time you want to type an apostrophe (which is a real pain) just tap and hold on the exclamation key and a hidden apostrophe option will appear - then just slide your finger up to access it.
To go a step further, go through all the keys. You will find some other less commonly uses
symbols and letters on other keys. Not all of them have hidden content.
"iPad Tips and Tricks: Hidden apostrophe key on the keyboard "
Reference : top-ipad-video-converter.com