I remember going to a dog park where a little 4-month-old Boxer puppy ran around jumping on everyone. The dog was not heavy enough to knock most of the adults down. However, it left everyone with muddy pants and the dog was big enough to knock over small children. The owner did nothing to stop the jumping puppy. After all, it was just a small pup. Everyone around her was pretty annoyed at the muddy prints the dog was leaving all over their clothes. That is an owner who will have a problem with her dog jumping on people when it gets older.
Dogs with poor social skills oftentimes just don’t know better. They will bounce off of everything, jump on everyone, run around like crazy, and investigate everything they can get their paws, snout, and eyes on! These dogs can come from any background, whether a rescue or puppy from a great breeder; if they haven’t had experience in new places and new situations, this can be how they respond.
You shouldn’t stop this type of jumping. You need to diagnose your dog's issue and remedy that. If your dog is just stressed being in a new situation, you should calmly get them off of you, offer them a treat to calm them down, and have them sit politely beside you until their stress level has subsided (or take them somewhere else so that they can calm down if it is taking a while for them to calm down.) But most of all, please do not just ignore this behavior change.
Puppies in human households try to lick the weird, flat, usually bald body part we have instead of a muzzle. When a cute little puppy jumps up to lick face, many people can only say “Awwww!” Hey presto! Jumping up has been rewarded. The puppy’s natural inclination is now a learned behavior. Too bad for the dog when he’s nine months old, bigger and less cute, muddying the pinstripes and knocking Granny to the ground.