The packers will come to your home with packing materials such as tape, moving boxes, and bubble wraps, and so on to get all your items loaded up in moving boxes. It is important to have a pre-move survey, so the packers will know which packing materials will be required for your packing.
It is unlikely to be able to supervise packers when they are many, so it is advisable to pack the items you are not moving to a separate box and label it “don’t move” or store them away in your garage.