How to Create a Custom App in SharePoint 2013
You create a custom app using the Custom List app. The Custom List app creates a very basic list app that you can then customize for your particular scenario.
Follow these steps to create a custom app:
Click the Settings gear icon and select Add an App. The Your Apps page is displayed.
Click the Custom List app on the Your Apps page.
The Adding Custom List dialog box appears.
Provide a name for the app in the Name text box.
To make things simple, you only need to give your new app a name. However, if you want to provide a description, you can click the Advanced Options link.
The name you type here is used in the app’s web address. Avoid using spaces in the name when you create the app. You can change the app’s name to a friendlier name after you create it.
Click the Create button.
SharePoint creates your new app and takes you automatically to the Site Contents page. Your new app has a green New! tag next to it to let you know it is a new app.