A will must meet the requirements of the state in which it was made. Each state has laws on the execution of wills, and while these laws are often similar, they are not always the same. For example, some states allow wills to be handwritten, while others do not. State laws also differ on the placement of the testator's signature (e.g. whether it must be signed on every page, signed only at the end, or signed anywhere on the will).
When making a will, you need to ensure it conforms to the laws set forth in your state. If it does not, it could be deemed invalid, in which case your state's intestate succession laws will determine the distribution of your assets. That may be very different from the way you would have preferred.