Your executor must be well aware of their role and responsibilities in advance of your death. They should be aware of the location of your will and your end of life wishes so that they can be prepared when the time comes.
You should also advise your executor that you are using the Cadence Legacy Planner. Let them know they will be given instructions for accessing the Executor Assistant app upon your death.
Since your executor will be coordinating with your family and trusted professionals, they should have the contact information of these people in advance. They should also know about any life insurance policies or trusts and should have a list of your assets and liabilities.