Power of Attorney
A Power of Attorney is a legal document authorizing a person to act as an agent on your behalf. This document is only effective during your lifetime, not after your death. A Power of Attorney can be used to transact various financial-related tasks if you are incapacitated or otherwise unable to do so for yourself.
If you do become incapacitated without having assigned power of attorney, the court will step in to appoint a conservator. Why do you want to avoid it? Because it is expensive, it is slow and it is public. Moreover, the person chosen by court may not be someone you would have picked.