A native application is a software program built in a particular programming language for a certain platform or device. It is the most costly thing to do in web development and requires an extreme amount of work. It is hard to create, is really finicky, and requires lots of updating.
Native apps have similar problems with emails. While in email marketing, you have to deal with multitudes of devices, browsers, and operating systems, native apps need to work for all the versions of iPhones, Androids, and iOS. Of course, each of these is coded in different languages as well.
Mobile apps really took off in July 2008, when Apple launched its first 500 apps via its app store. Before this, only early PDAs like Snake on the Nokia 6110 phone had been available.
It became and still is one of those buzz marketing tactics businesses think they should do when really creating an app as a business should be the last option considered. If you can avoid creating a native app, do it because it will cost you lots of time and money!
What a native app does allow you to do is to have an app on your phone. It loads up the app and hooks into your system. The best reason for creating an app is when you need to use the phone sensors like the accelerometer, exact GPS coordinates, camera, or need information entirely available offline.
Another issue you must contend with for native apps is the app stores themselves. They have different rules, regulations, and procedures to validate an app is worthwhile to put on their app store. You are better off trying to build a cross-platform mobile application, or better yet, developing a responsive website on both mobile and desktop.