If you don’t name anyone, state law gives control of your body to your next of kin, in an order each state sets.[5] Most states let you name someone else in a signed document, and some build the choice into their official forms. Maine and Maryland include it in their advance directive forms, and North Carolina includes it in its health care power of attorney form.[5]
A few states do it another way. In New Mexico the person carrying out your funeral wishes has to be named in your will, South Carolina requires a will or another verified and attested document, and in Massachusetts the personal representative named in a will may carry out your written instructions.[5]
Two cautions from the Funeral Consumers Alliance. A will often isn’t read until the funeral is underway or over, so instructions that live only in a will can arrive too late. And the person you name isn’t obligated to carry out wishes that are illegal, highly impractical, or more expensive than the money you left.[5] Pick someone who’ll follow through, tell them, and set the money aside.
Your state’s rule, and whether it has an official form, is in your MORTL state guide under “Naming someone in advance.”