When looking to change unwanted behaviour, whether jumping on guests or barking at other dogs. taking steps to eliminate the opportunity to continue to practice those behaviours is an important part of the process.
Every time your dog has the opportunity to jump on someone, that behaviour gets reinforced. Any behaviour that is reinforced gets repeated.
For example: jumping on guests. When you are ready to change it, it's essential to stop all reinforcement of the jumping. You may be saying " But I don't reinforce it".
If your dog is making contact with your body, you are pushing him off, you are saying "no!", you are staring at him, then you are reinforcing the behaviour of jumping.

Decide what behaviour you prefer - sitting at the door? holding a toy in his mouth? chasing a ball? lying down? going to a dog bed? The choice is yours and what works for you and your family.

The process is the same. First, prevent your dog from getting to the door by using a tether, leash, baby gate or crate. Second, set your dog up to do what you want and reinforce it.
If you want your dog to sit you need to reinforce that behaviour. Set him up to be successful by keeping him away from the front door using one of the above methods. Either ask for a sit or wait for your dog to sit on his own. Reward heavily when he does. Repeat, repeat, repeat.
I prefer to wait for the dog to figure out what he needs to do. It can take longer but I like thinking dogs.

A huge reward for sitting politely while people enter is to "go say hi". If your guests are good at following instructions you can have them help you train your dog to do this. They need to know they cannot encourage the dog to jump.
Have your dog on leash to prevent running to the door. Reinforce sit multiple times as the person enters. When your dog is showing some self control (not jumping around or pulling), cue "go say hi" and walk with the dog to the person. Have the person reach or kneel down to pat the dog.

This is not the best video but it gives an idea of what the behaviour looks like.