Puppies are constantly learning about the world and what behaviours work for them. This means that if you are not actively teaching your puppy to behave in the correct manner, he may be learning behaviours you do not like. One of these is the learnt behaviour of jumping up to get attention or when greeting you at the door.
When your puppy jumps up, it's only natural to want to lean down and pet them. However, this reinforces that jumping is a good way to interact and get attention from you. You may enjoy this obvious demonstration of joy and affection from your puppy, but when they are a muddy adult, jumping up is rarely welcomed! Worse still, if they jump up at others that can be unpleasant for all concerned, especially if that person is scared of dogs or has their best clothes on! It is best to train out this behaviour when your puppy is still young, in a calm and methodical manner. If your pup has already learnt to jump up then flapping your arms in the air in agitation and raising your voice can make things worse. Your pup may see this as excited or confrontational behaviour and jump up even more in an effort to appease you!
Training your puppy not to jump up
Stay calm and turn your back on your puppy whenever they jump up at you. Do not look at or speak to your pup if he is jumping up so you are not rewarding him with any interaction while he's jumping. However, the second that he's stopped jumping and has all four feet on the ground, then turn around and give him the attention he wants, but in a calm manner in order not to over excite him. Your puppy will then learn that not jumping up is how to get the greeting he wants. It is very important that all members of the family and all visitors behave in this same manner towards your pup. Keep your pup away from any visitors who will not follow your instructions. The more consistent that you all are the quicker he will learn the correct way to behave.