It is important that your puppy greets guests and strangers by sitting or standing rather than jumping up. When you meet someone, ask your puppy to sit or stand. Ask the person to only come forward to greet your puppy when he is sitting/standing and to back away if he jumps up.
Doing this consistently with several people will soon teach your puppy that it is more rewarding to sit than to jump up. Ask people to come to the house especially so that you can take time practising this exercise until your puppy sits automatically when greeting someone.
Make sure that everyone in the family greets your puppy when he is sitting or standing rather than jumping up. If he has good habits with his favourite people, it will make it easier for him to greet visitors well.