Understanding backend and frontend in mobile app

What is a backend app in mobile development ? Do you require a backend app on your mobile device? What are the various types of backend app? How do you pick the right backend app for your mobile device?
In case you have plans to develop a mobile app that is custom, you might have such questions as well as doubts regarding the backend development. Get to know about backend and frontend mobile apps.

Backend mobile apps
When thinking of mobile development, you can think of backend as a mobile app additional application. While frontend works in the frontend, the backend works differently. It is a software piece that tends to run on servers – which are remote machines.
The backend can be accessed via the internet through API. A backend is not supposed to be used directly by humans but instead by other applications such as frontend apps. Its primary purpose is to ensure remote tasks are performed which, cannot be performed by the frontend.
Frontend app
You might already have several applications that are installed on your mobile device. You might already be using apps such as Instagram, calculator, and Facebook messenger. All of them are frontend apps.
Any app that you can directly download from the App Store or Google play are all frontend apps. They are also mobile apps because they can run on mobile devices like your mobile phone. The apps that you can use to interact with on your wristbands, smartwatches, and another type of mobile devices, are frontend apps.
Another group of frontend apps is those who are not mobile apps. The apps that run on your car, fridge, desktop computer, or another type of device which you cannot carry along with you are not mobile apps but still are frontend apps.