How do I seal all my windows and doors ?

Call your local utilities dept. Ask if they have any weatherizing programs. A few years ago , they gave you free supplies, but that was in NJ. It can't hurt to ask. There used to be a product that used tape & clear plastic, you would put it around your window, then used a hair blower on it and it tightened it and made it draft free. For your door they make something that slides under your door. The center part is flat , that slides under the door , on either side is a round foam filled area that blocks drafts, you don't have to move it out of the way each time you open the door , like a draft sock. They cost $10-$15.

Try insulated window treatments over your windows. Here is some at Target online to show you what I am writing about. https://rstyle.me/n/dacghhcc4s7

Hi San, I know about this problem and am going to really take steps to combat it this year. This article looks pretty good and is easy to follow:

https://www.simplemost.com/diy-draft-proof-doors-windows-home/

Sandra, it looks like you have tried just about every cosmetic solution with no luck. As you say the problem lies with the shifting of the foundations and this is a very big problem indeed. (I wonder if you had an inspection done when you bought the house?) The cosmetics around the doors and windows are just symptoms of this bigger problem, and unless you do something radical and expensive, I fear the foundation of your house will always cause these problems. And probably get worse with time. The symptoms are just a smoke screen for something much more serious. This is obviously not a DIY problem and would need expert help from a professional company. Remember to check out references if you do decide to go this route. This article may give you some indications of what would be involved. I wish you good luck.

https://www.myfoundationrepairs.com/foundation-shifting-moving/

Sounds like you might have air infiltration around the windows and doors themselves. Get a lit incense stick and hold it in front of the area around the door in front of the door trim. Lots of time, that area was not insulated, you can jimmy off the wood trim, and then either use the pink insulation cut into long strips and force it into the gap or use Door & Window foam caulking... then replace the trim. https://www.youtube.com/watch?v=0T_vP2l8LOU&t=403s

Then if the door jam itself has a gap around the door, I would buy some of this, works best on gaps and old doors.... https://www.youtube.com/watch?v=iDMZz4HIURw I got it at True Value hardware store.