I tried to block the YouTube and Facebook app in my smartphone from
the mikrotik , but I cannot.
 The mikrotik block only the site not the application.
 What technique I can use to block YouTube and Facebook in my smartphone?
Another question : is there a way to define from the mikrotik how much

Thanks
Justin

Use personal firewall on your smartphone to block the application right there.

Or better. Uninstall it.

What is your method to block website? Layer 7 or rule only?

you need to use a regular expression to block all youtube URL's used for the phone App.

You can see this video to know how to configure it:
https://www.youtube.com/watch?v=6oAiUGAsfEY