How do I import Notes from my iMac to my iPad? Notes from my iMac do not appear on my iPad or iPhone, what could be wrong?
This is most easily done through iCloud, which should be the same account you sign in to the App Store with. 

Go to System Preferences > iCloud. If you haven't already set up your iCloud account on your Mac, simply click on iCloud, and enter the username and password.

In the right side field, scroll down to "Notes" and tick the checkbox next to it. You may need to wait 5 or so minutes for iCloud to update.

On your iPad and iPhone, go to Settings > iCloud, scroll down to Notes and turn on the slider.

For additional setup info: 
https://www.apple.com/icloud/setup/mac.html