The quickest way to get Help for a third-party app is to view its properties and then click the Help link. Help links are an option that can be built into SharePoint web apps.
Note: Built-in SharePoint apps do not have a Help link. To get assistance with specific built-in SharePoint web apps, search the support.office.com website.
View Help in a third-party app
From the SharePoint Site that has the app, click Settings and then click Site contents.
Under Lists, Libraries, and other Apps, find the app for which you want to view Help.
Point to the app, click the ellipses (...) and then click Help in the callout.
Third-party Help can appear in the form of a pop up page or it can take you to the publisher's website.
If you do not see a Help link, then the developer who created your app has not made Help available for the app. If you see an About link, you can also click that to view additional information about the app.