this is from an American drama "How I met your mother"
When I say "suit up", I wish you 'd put on a suit.
But, what would be different if I say like the following?
When I say "suit up", I wish you put on a suit.
ps. he isn't wearing a suit
"You'd" is a contraction that can stand in for either "you had" or "you would". The difference between the two phrases is context and timing.
If the statement is spoken before event, it can express a desire for the person to wear a suit to that event, that's the "you would" version - "I wish you would put on a suit [before we go]."
If the statement is spoken at or during an event, both versions mean the same thing. "I wish you [had] put on a suit [before we got here]."
Part of the confusion is that "put on" doesn't change spelling or pronunciation when the tense changes. If you substitute "wear", it becomes less ambiguous.
The last two statements are equally correct, but the mean of "you'd" is no longer in question.