Depending on the state, advance directives come in two parts. One directive is a living will, which describes the kind of life-sustaining medical treatment a person would want or not want if terminally ill or with no chance of recovery. The other is a health care proxy, or a medical power of attorney, which names an agent to make medical decisions.

Advance directives typically cover permanent unconsciousness, an irreversible fatal illness or severe brain damage — all with no expectation a patient would recover and have a meaningful quality of life, Ms. Whitman said.

“This is a high standard,” she said. “Ending life-sustaining treatment would require a very dire situation in the opinion of a physician.”

Ms. Barney said it was best to name just one person to be a health care agent. “It is very difficult if the doctor needs to talk to two people if they do not act together,” she said. And if someone is drawing up documents now, she said, it may make sense to choose an agent who lives close by, given travel difficulties since the coronavirus began spreading.

Also included in the documents should be a HIPAA medical records release form, which would allow health care providers to provide private information to approved family members, friends and others.

Parents of college-age students and single adults in their 20s should ask their children to sign their own HIPAA release and perhaps an advance directive, lawyers say. Without these documents, once a child turns 18 or 21 (depending on the state), a parent cannot make decisions related to his or her care and may be unable, depending on a physician’s discretion, to get information on a child’s condition.

Also, it is imperative to review, and perhaps update, beneficiary designations on retirement accounts and life insurance policies, experts say. A beneficiary designation on an individual retirement account or a company 401(k) account, for example, would override any instruction in a will for that asset.