As a part of estate planning, you can use a power of attorney form to plan for periods when you lose capacity to make decisions for yourself. The power of attorney is a legal document in which you can state that you want another person to make decisions on your behalf. In this arrangement, you are called the principal, and the person who acts for you is called the agent.
You can create a general power of attorney, which would entitle your agent to do any act on your behalf that you have the legal authority to do, such as making all healthcare and financial decisions. Otherwise, you can make a specific power of attorney and authorize only one or a limited number of acts, like paying your bills.