A letter of wishes is a settlor of a trust's non-binding expression of intent to trustees. It provides direction and guidance in the desire of the settlor. The document may also contain a will maker's additional directions addressed to the executors of a will.
It is not legally binding as a will is. It may be used to give gifts of sentimental value, express funeral wishes, advice to the guardians of your minor children on how you want them raised, etc.. Also called a side letter or memorandum of wishes.