A DNR is not a document you write — it is a medical order signed by a physician and entered into your care record. That distinction is the one that matters. Advance directives express what you want; a DNR converts a wish into an instruction that clinical staff act on immediately, without needing to locate paperwork or interpret anything in a crisis.
Its scope is narrow and frequently overstated. A DNR addresses one thing: whether cardiopulmonary resuscitation is attempted if your heart stops or you stop breathing. It does not mean treatment is withdrawn. Patients with a DNR still receive antibiotics, pain relief, oxygen, surgery, and every other intervention their care requires. Families who believe a DNR means "do nothing" often resist one for the wrong reason.
The forms and their legal weight are set by state law, and they vary considerably in name, color, format, and whether they are recognized outside a hospital. Many states operate a separate out-of-hospital order, sometimes issued as a bracelet or a form that must be physically visible, because paramedics arriving at a home will begin resuscitation unless a valid order is in front of them.
DNRs are generally discussed when someone has a serious illness or is nearing the end of life, in conversation with a physician rather than filled out ahead like a will. If you would want one under defined circumstances, record that preference in your advance directive and raise it with your doctor.