No. You do not have to make a Personal Directive – it is optional and voluntary. While there are good reasons to make one, you don’t have to, and no one can make you sign one if you do not want to.
Even service providers (such as doctors or care facilities) cannot require clients to have a Personal Directive. For example, the Personal Directives Act makes it an offence to require a Personal Directive as a condition of obtaining residence or continuing as a resident in a care facility.