The will itself is the central document in most people's estate plans. As of 2010, all 50 states accept wills that are typed or handwritten on paper. However, only a few states accept an oral will, and only Nevada accepts an electronic will. Consult an attorney to determine how to make a valid last will and testament in your state.
A codicil is an amendment to your original will. It can change a large or small portion of your will. Like your will, a codicil must be in writing, signed and witnessed according to the specific laws of your state, and attached to your will so that it is not lost or forgotten after you are gone. If you want to change substantial portions of your will, you may wish to write a new will instead of using a codicil.
Personal Property Memorandum
If you want to leave particular items to particular people, you may wish to attach a personal property memorandum to your will instead of making the list in the will itself. A personal property memorandum lists each item you want a particular person to receive, then lists the name of the person you want to leave it to. In most states, you can change a personal property memorandum more informally than you can change a will. For instance, you may be able to change the personal property memorandum simply by crossing out a line and writing the change in, instead of having the memorandum signed and witnessed with the same formality as your will itself, according to Offutt Air Force Base's Legal Office.
A self-proving affidavit is not required in any state to make a valid will. However, it can be useful after you are gone by speeding up the probate process. A self-proving affidavit is a signed and notarized statement made by you and your witnesses, stating that your signatures are all valid and that you know you have signed or witnessed a last will and testament. States that accept self-proving affidavits use them as evidence that your will is valid, instead of requiring your witnesses to testify in court that they signed your will.