How does Apple add healthy widgets?

Take the iPhone 7 mobile phone as an example, the adding method is as follows:

First, turn on the iPhone 7 phone, then slide to the right on the desktop, bring up "Edit" on the phone desktop and click Enter.

Second, after entering, the existing widgets are in the red box at the top of the page, and the programs that can be added are in the red box below.

Third, then select Add to Application. Take Baidu as an example, click Add.

Fourth, then back to the mobile phone desktop, we can find that adding Baidu application widgets is successful.