A voice told him to kill and eat the animals. Peter replied he never ate unclean animals and neither would he eat them in the future. And this was repeated three times. And the vision was over. We read that Peter wondered what the vision meant.
Visions are always symbolic.
Some people read Revelation 13 and read about a mark in the right hand or forehead of people, and are looking for computer chips on the right hand as the mark of the beast. But we need to notice that John saw a vision when he saw that picture. It represents something. Visions are not to be taken literal. So the eating of unclean animals meant something and symbolized something that Peter did not first understand.