The requirements and capabilities of living wills vary from state to state, so it's a good idea to know some of the basic laws for your state. It's also a good idea to update your estate planning if you move to a new state, because you don't want to discover that your living will isn't valid when it comes time to put it into practice.
A living will isn't the document that lays out how you want your assets to be disbursed among your heirs. That's just called a will. A living will is what you use to make your health care decisions known if you are ever unable to communicate them yourself. A will comes into play after you pass away; a living will comes into play when you are still alive.
Living wills are also referred to as health care directives or advance health care directives. They can also be couple with power of attorney documents or legal structures if you want to both make your wishes known and appoint someone to make some decisions on your behalf if you are ever incapacitated.
Because these documents are relied on when you aren't able to make decisions or community for yourself, you certainly don't want them to be found invalid at that time. Ensuring you follow state law in creating the documents can help you avoid that.
In California, either a durable power of attorney or an advance health care direction require certain structures. Most specifically, they have to be signed in the presence of two witnesses -- who also sign the document -- or a notary. Living wills are also not valid and may not be adhered to if you are pregnant at the time of the medical emergency or incapacity. Working with an estate planning professional can help you ensure you understand how state laws impact your plans and wishes.
Source: FindLaw, "Living Wills: State Laws," accessed Feb. 17, 2017