Whether it's an iPhone, iPad or Android device, the human who owns it uses apps.
Apps can be created to improve your internal business systems and to provide new ways to interact with your customers.
Once your app is ready to go it will require distribution. Distribution is simply how you get your app to your customers or employees.
The type of app will usually dictate which type of distribution you need and each option has pro's and con's, so you have to decide which method will work best for your situation.
Both Apple iTunes and Google Play offer public and private distribution. Just be aware, there are different fees and procedures for each so it is worth knowing about before you commit to a platform.
While there are many different devices on the market, the real battle which is relevant when it comes to building apps,relates to the operating systems (OS) which run the devices.
In this case, there are only two options worth targeting right now, Apple with iOS and almost everyone else with Android.
Right now when it comes to smartphones, the market share of iOS devices and Android devices is approximately equal with the smallest of margins, 1% going to Android.
Looking at tablets the numbers are roughly the same, with Apple iOS enjoying 46% of the market and Android taking 49%.