The two witnesses are not identified specifically, but Moses and Elijah's miracles will be featured, so many Bible scholars contend that they will be the two witnesses. Some think they will be Enoch (because he was caught (translated, raptured, snatched up before the Great Flood, symbolic of believers who will be snatched out before the Great Tribulation) who never physically died and Elijah who never physically dies, as he was caught up in a whirlwind.
I do not know, but I believe it was EITHER Enoch and Elijah or Moses and Elijah.

Deuteronomy 34:6 states that God, after showing Moses the land which He would give to Israel, buried Moses in the valley in the land of Moab. Verse 5 said that he died and verse 6 says that God Himself buried Moses....so he experienced the physical death. That's why I think the two witnesses probably are Enoch and Elijah.....but because of Moses' miracles reenactment....I'm not sure. I don't know. Likely Enoch and Elijah. It really doesn't matter, since they are God's witnesses and they are going to glorify Him!