There's not really any 'Plato.'

It's all allegedly Socrates in his dialogues.

But a lot of that content is credited to Plato instead, and in many cases it probably is his own stuff being put into the mouth of his more famous teacher at the time.

(In particular, I tend to get the sense the parts that end up as long monologues that are unequivocally being agreed with by the other person tend to be Plato's own stuff, as Socrates seemed to like nothing better than disagreement and in the genuine strong parts will even be his own devil's advocate if no one else stepped up.)