A letter of instruction (LOI), also called a letter of intent. It provides your executor with important information about your assets and personal information.A letter of instruction is a cheat sheet for anyone involved in settling your affairs. Unlike a will, this letter has no legal authority. A letter of instruction can complement an estate plan and provide your loved ones with additional details about your assets and wishes after death. List specific account numbers and what banking institutions or insurance companies you use. A letter of instruction is a nonbinding document that explains your personal preferences and last wishes in plain language. For example, you might write a heartfelt letter of instruction to children or other heirs about how you wish their lives to be. Turn over all checks made out to me, or in our joint names, to our executor. Letters of instruction can also be a "cheat sheet" for important details that aren't in your will.