Record what you want
Twenty-five short questions covering body care, the service, disposition, the people involved and what happens afterwards. Concrete prompts (burial or cremation, religious or non-religious, music, readings, pallbearers, flowers, ashes) with a sentence of guidance on each. Together, the answers serve as a written expression of wishes for your family to follow. Answer what you have a view on; leave the rest for your family to decide.
Hand it to whoever arranges things
When the case transitions to bereavement mode, every wish you have recorded is visible to your nominated successor and to the funeral director, if they are on the case. Twelve of the wishes also appear as notes against the matching steps in the funeral-arrangements section, so the family sees each one at the point a decision needs to be made. For other wishes that fall outside the funeral itself (charitable bequests, personal messages), the wiki has guidance on writing a separate letter of wishes.