There are several types of apps
Web application – A website that can be accessed through a browser on your computer. It can be a portfolio website for my business, or an online store and even a site for the company use only. Keep in mind that if the website addresses its customers, it is advisable to build it adapted to mobile devices. Mobile web does exactly that.
Mobile web – It is basically a regular website that can be viewed through a browser, but since it is built in a responsive way and responds to the size of the device that’s been used (due to the components inside that are rearranged depending on how much space they have on the screen), it can also be browsed conveniently using mobile devices. Like a regular website, you can request location access, manage registration using social networks, and more.
Android – An application to be uploaded to Google Play. Can communicate with the device to receive information like user contacts, calls, media, location, push notifications. Usually also includes a server side that manages the logic and database for the application.
Ios – An application to be uploaded to App Store. Can communicate with the device same as Android Apps. But the development for Ios is usually done in a different language and requires two different apps.
Android + Ios – There are tools today that lets you develop for both platforms all in one place. This presents a significant advantage that can save time and money, keep the apps consistent and allow new updates to be released easily. The disadvantages of this approach can be in performance (in case of heavy applications like games or video editing, which are better be developed for each platform separately), compromising on unique components that Android and Ios applications have, and development process that may include a lot more coding in order to bridge these gaps