Puppies and dogs naturally jump up on people when they say hello. Why? because we are taller than they are and when dogs meet, they sniff each others faces. They like to do the same thing when greeting us, so it is perfectly natural for dogs to jump up on us to try to reach our faces and get our attention.
It is important to teach your dog what you do want her to do during greetings. For example, you can train her to sit or stand to greet people instead of leaping all over them. The following exercises can help your dog learn to greet you and others politely
When your dog starts to jump up, stand still, look straight ahead (not at your dog), and pull your hands and arms up to your chest. Calmly wait for your dog to stop jumping. When her front paws touch the floor, immediately look at her and calmly stroke her. If she gets excited and jumps up again, straighten back up and repeat the sequence.
If your dog already knows how to sit on command, try this. When your dog starts to jump up, stand still, look straight ahead (not at your dog), and pull your hands and arms up to your chest. Say "Off" and immediately turn your back to your dog so that she cannot reach your face. Then say "Sit." When she sits (watch her in your peripheral vision so that you can see), turn back around to face her, kneel down and calmly stroke her. If your dog jumps up again, quickly stand up and turn your back on her as you did before. Keep repeating this sequence until your dog stops jumping up.
If you are entering a room and your dog starts to jump up, immediately step back outside and close the door behind you, leaving it open just a crack. Through the crack in the door, say "Sit." When your dog sits, calmly walk back into the room, kneel down and gently stroke her. If she jumps up again, quickly stand up and walk right back out of the room again, closing the door behind you. Keep repeating this sequence until your dog stops jumping up.
When your dog starts to jump up, stand still, look straight ahead (not at your dog), and pull your hands and arms up to your chest. Say "Off," and take a few quick steps toward your dog, be careful to not step on her toes. The dog will jump back to get out of your way. The instant the dogs front paws are on the floor, say "Sit." When the dog sits, kneel down and calmly stroke him. If the dog jumps up again, immediately stand up and repeat the sequence.
Once your dog has learned to greet you politely, recruit friends and family to help you teach your dog to greet visitors politely as well. One at a time, have your friends practice the exercise above that starts with the person entering the house or room. Explain the sequence to them: turn their back, walk out and close the door if your dog jumps on them. Then start your practice session with one of them knocking or ringing the bell, and go with your dog to answer it. Before you open the door, tell your dog to sit. When the dog sits, open the door. If your dog jumps, your friend knows what to do. If your dog stays sitting, your friend can calmly greet her and you can praise and treat her. Have each of your friends do several repetitions.