In this guide, we'll discuss the process of creating a Trust-Based Estate Plan and how to transfer bank accounts to your Trust. Our Certificate of Trust and the stock power properly signed.A letter of instruction, also known as a letter of intent, is an estate planning document that provides a variety of information. This guide is designed to teach you how to write a letter of instruction for heirs, or anyone else who may benefit from a little more direction. Grab a piece of paper (or open a computer file) and start with "Letter of Instruction. Laws, cases, and web sources on the law of trusts in Massachusetts. It's an informal document they can read that tells them about your financial and personal matters that will need their attention. Laws, cases, and web sources on the law of trusts in Massachusetts. A letter of instruction, or letter of intent, is a simple document that can take the guesswork and headache out of settling your estate. Step 2 - Complete the Document.