When you create an app you choose the type of template it should use. There are templates for things like libraries, lists, calendars, tasks, and discussion boards. When you add an app to your site you give it a name. For example, you might add a Calendar app and call it Company Holidays.
What can be confusing is that apps are often named the same thing as their templates. For example, if you are using a site with an app called Document Library based on the Document Library app template, then understanding apps would be very confusing. If you create your own app called My Documents App and then choose the Document Library template then the differences are easy to notice. You can see that you could create a My Documents App 1, My Documents App 2, and My Documents App 3, which could all use the same template: Document Library.
The apps that you have available depend on the SharePoint 2016 edition you are using as well as the features you have activated. For example, the Report Library app is only available with the Enterprise license.The following are common apps that you should be aware of.
- Document Library: Used to create apps that hold documents.
- Form Library: Creates an app that holds business forms. This library requires a compatible editor such as InfoPath.
- Wiki Page Library: Used to create apps that store wiki pages.
- Picture Library: Using this template you create apps to store pictures.
- Links: Creates an app that contains HTML links.
- Announcements: Results in an app that can be used for announcements.
- Contacts: Creates an app to store contacts.
- Calendar: A template used to create calendar apps.
- Discussion Board: Creates an app where users can discuss topics in a threaded forum.
- Promoted Links: An app template that creates a place to store links to specific actions using a visual tile based layout. When you create a new Team Site it includes an app based on the Promoted Links template. When you move the mouse over a tile, information pops up to describe what will happen when the link is clicked.
- Tasks: A template used to create apps to store tasks.
- Issue Tracking: Used to create an app to track issues.
- Custom List: A template that creates a blank app based on a list.
- Custom List in Datasheet View: This template is similar to the Custom List template but provides a datasheet view by default.
- External List: Used to create an app that connects to external data.
- Survey: Creates an app that is used to conduct surveys.
- Asset Library: A template used to create an app that stores site assets such as images, audio, and video files.
- Data Connection Library: Creates an app that stores data connections.
- Report Library: Used to create an app to store reports.
- Access App: A template used to create an app that is the Office Access web based app.
- Import Spreadsheet: A template used to import a spreadsheet. The result is an app that contains the data in the spreadsheet. The equivalent could be done manually by creating the app using the Custom List template, adding all of the columns in the spreadsheet, and then keying in all of the data.