Maya recently explained how Santa gets all of the toys on his sleigh.
He has multiple sacks on his sleigh, one per family and they are labeled with the families names. Using his magic, he shrinks the sacks down to fit on the sleigh. Once he arrives at each house, he uses magic to get the appropriate sack to the top of the pile and un-shrinks it. After everything is normal size, he brings it down the chimney.