You can take either a stem cutting or a leaf cutting to propagate your jade plant.
Stem cuttings: Remove stem cuttings using a clean, sharp knife or pruner. Tip cuttings 2 to 4 inches long are best, making sure to remove leaves from the bottom of the cuttings. A rooting hormone may speed the process but is not necessary. To stick the cutting. open a hole in a well-drained rooting medium using a pencil as a dibble, and insert the cutting just deep enough for the cuttings to stand upright (usually 1 to 2 inches). After you insert cuttings, water them to firm the rooting medium around them. Allow the medium to be on the dry side to prevent rot.
Leaf cuttings: Leaf cuttings may consist of only the leaf blade or the leaf blade and petiole. Leaf cuttings are successful for only a few specialized plants and require a longer period to generate a new plant. Rex begonias, bryophyllum, and jade plants are commonly propagated by laying the leaf flat on the medium.
When rooting a jade leaf, let the leaf air dry several days before placing it on the rooting medium. Be sure to keep the medium slightly dry to avoid rotting.