I was invited to UCLA Anderson's round 2 interview last week (had mine on Wednesday) and was also required to submit official documents. In this case, UCLA is asking for the documents to be sent directly from the candidate's university. The documents required are
1/ Official diploma or a certification letter.
2/ Official transcript.
They can be sent electronically or physically, but the sender has to be the university itself. Previously, I tried sending UCLA scanned copies of my diploma and transcript but was informed those are not eligible. Hope this clears up some confusion.