On site and mobile application, specific or supposedly sensitive information requires access to an API.
In the webs of these sites / app you commented on, they use an API that gets the data needed to create spreadsheets, calendars, and reports for the final user.
If your intent is to create an application to get data from a company or company, you need to know if it provides an API or the information you need.
Most common examples are applications that use data from Facebook, Instagram, Twitter, and more.
If you have questions about how to get started, visit the Google Developer Website.
