A Living Will is quite a different thing from a Will. They are more commonly known these days as Advance Directives.
An Advance Directive is concerned with medical treatment only, and takes effect during their lifetime. Any wishes you have about how your property is dealt with after your death or about your funeral should go in your Will and not in an Advance Directive.
In England, doctors have to take into account the wishes of an adult patient who is conscious and is mentally capable. However sometimes people are worried about decisions that might be taken while they are unconscious or not capable of making a decision.
An Advance Directive tells the doctors what you want to happen in certain circumstances if you are not capable yourself of telling them. In the document you can say what you want or do not want in those circumstances if you are receiving medical treatment. Although people often make Advance Directives when they are well and healthy, these documents usually envisage the situation where a person might have a terminal illness and deals with such matters as particular types of medical treatments they may or may not want to have and whether there is a particular person that they would like consulted about their treatment.
Sometimes this can overlap with a Personal Welfare Lasting Power of Attorney – see our page about Lasting Powers of Attorney.