Legal Question in Wills and Trusts in California

The handwritten portions might cause some confusion but it would not void the instrument. The problem will be that unless you initially and dated it, no one but you will know if you made the notes before or after signing the document, or whether it was you or someone else who made the notes, is it an attempt to amend the trust language, or what. It might be best to prepare a new one if you do want to make significant changes. if the notes are just notes to yourself and not meant to be binding, prepare a separate sheet that you attach to the trust documents saying that.