How to show notifications?

I want to show notifications on a particular line, when the user does some mistake in the syntax.

Which is the best way to do that?

Also, i want to do something like how store app notifies user saying "Your app is installed" on the top right of the screen(sorry, i dont know the name of it).

Thanks in advance, any code help will be more helpful.

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pradeep aj If it answers, then please Mark it as Answer