Platform: iOS, Android
Skype is one of the most-known communications software and is available for just about any platform. Tablet Skype apps can use wifi or cellular connections to text, talk, and video conference with other Skype users. Skype-to-Skype communications for individuals is mostly free, though there are some limits to the free service, such as the inability to have group-video with the app. App calls to landlines also require credits that can either be purchased through the app or from the Skype website.
Skype's low (to no) cost and easy setup generally makes it the go-to communications program for simple one-to-one connections. However, more complex needs may not be covered by the mobile application.