I always wondered. My house is owned jointly by myself and my wife. Were
On the deed. To enjoyed a joint tenancy. But if we were both to died.
Then what. I have a 25 year old son. I have no will. Would having a
Will help? How can I arrange for my son to get ownership

If one of you died it would go 100% to the surviving spouse. They would then have the right to leave it to whoever they wanted. If they died with no will, it would first go to their children if they had any, or if not it would follow the rules of beneficiary succession when dying intestate (without a will).

1. Get a will

2. It wouldn't necessarily go to your son. If you have debts, it would become your "estate" and go to paying those off.

Absolutely get a will. There are a couple of forms of joint tenancy (some with survivor ship of the other joint tenent and some without. But the previous post is right on... get a will. They're cheap and will save your son a lot of headaches.