You don't want to risk that someone gets possession of photos, email, messages and other personal data when you sell or give away your iPad. It's easy to reset it. Here's how you do:
Open Settings > General > Reset > Erase All Content and Settings.
Follow the instructions.
If you have activated Find My iPad you will need to enter your password to unlock it.
A reset sometimes solves problems with the iPad too. Just remember to make a backup first.