How does php click the button to send information to WeChat applet or applet page?

I understand what you mean is to control the function changes and interface changes of WeChat applet through the background.

It depends on how your applet was implemented at that time. If the front end of the applet is vue, it is actually easy to implement.

Everyone in the front end writes several different sets of ui and loads different css.

In this way, the background can let users see different styles through different user roles.