Your will is not just a piece of paper that has your wishes in words and written in ink. It is an expression of what you want to have done once you are no longer on this planet. You can get help in making a will as there are lawyers who do nothing but that or you can write your own and have it made legal. You can get your witnesses to be there when you sign so that no one will question your words later.
Your will must be in writing. You cannot make a video tape of what you want to leave to who and how your body will be treated after you are gone. You also cannot just tell someone your wishes and feel that it will be legal as oral wills are not legal. So when you put your words into your wishes, make sure it is readable. If you have words that cannot be understood, then they will not be enforced.
If you cannot sign your own name or write your own will, you can get someone to write it for you. A lawyer would be a better choice than a person who is a beneficiary in your will. You just never know who will become greedy when it comes to financial matters, so be safe and have witnesses and legal papers. Your will must be in ink and not a medium that is easily erased as you never know who you can trust.