When creating complex and extended document libraries or other Apps, you can save this SharePoint App as a template that can be used on other libraries or apps.
Create a App with a newly created App template
1. On your website or team site, click Settings, and then click Site Contents.
2. On the Site Contents page, click the App on the three dots, click Settings.
The App Settings page opens.
3. On the Settings page, click Save document library as template.
4. On the Save as Template page, in the File name, Template name and Template descriptions fields, type a name and description for the template. Click OK to save the template.
5. Go back to the Site Contents page, click Add an App.
6. In the Your Apps page, search for the created App Template with the search box.
7. Click the App you want to add. Give it a name to start creating it.
8. Your App is now available in the Site Contents page. You are now able to create or edit a navigation link for the App.