Question

e.g. It is easy to draw cartoons.
In this sentence 'It' is a formal subject and 'to....' is a real subject.

(Is the expression correct?)

Answer 1

Yes, "It" is the subject.

"To draw cartoons" is an infinitive phrase used as an adverb, modifying the adjective, "easy."

http://www.chompchomp.com/terms/infinitivephrase.htm