Welcome to iMore! You can use iMessage with other iOS users. To get iMessage working, you'll need to set it up on your iPad first, but luckily this is just a matter of going into the settings and signing in with your Apple ID.
First, go to the iPad Settings by tapping the icon that looks like gears turning.
Scroll down the left-side menu until you locate Messages. Tapping this menu item will bring up the iMessage settings.
Flip the switch for iMessage to the On setting. This will prompt you to login with you Apple ID.
Once logged in, you should see your the email address you use with your Apple ID in the "Receive At" section of the settings. If you'd like to receive text messages at a different email address, touch the "Receive At" setting and then touch "Add Another Email..." to add the new email address. You will be sent a verification email, and after verifying, you will be able to receive text messages at that address as well as your main address.
You'll also need SMS for texting with non iOS users. Here's an article on how.
http://m.imore.com/sending-and-recei...mite-explained
You can use FaceTime for calling other iOS users. I'm not sure about Skype. Maybe someone else knows that.
Sent from my ancient but trustworthy iPhone 5.