"You did it" at a certain time in the past (e.g., last week). "You have done it" at some point in your life until right now. One is the simple past tense, the other is the present perfect tense. Examples: I visited Rio during Carnival in 2004. I have never visited Rio during Carnival, but I hope to go someday.

you have done in present perfect you did in simple past

When we talk about a period of time that continues from the past until now, we use the present perfect (you have done/been/travelled,..) Have you read Hamlet? No I haven't The past simple (something happened) tells us only about past. She passed her examination because she studied very hard.