One deals with your life before death and the other your wishes after death.  Essentially an Advance Care Directive is a legal form that allows people over the age of 18 years to: write down their wishes, preferences and instructions for future health care, end of life, living arrangements and personal matters and/or appoint one or more Substitute Decision-Makers to make these decisions on their behalf when they are unable to do so themselves while they are still alive.  A Will outlines what you intend for your assets and your children following your death.