Your attorney in fact can pay bills and taxes, invest in stocks and bonds, buy or sell real estate, collect benefits or handle retirement accounts. Some things can't be delegated, like voting or writing a will. If you run your own business, your agent can do anything you would to operate the business. He or she is expected to be honest and responsible, keep good records, not mix your funds with his, and avoid "conflicts of interest" -- gaining personally from serving as your agent.
This attorney in fact makes medical decisions when you're unable. They select doctors and hospitals, help decide on your admission or discharge , pay medical premiums, keep track of claims, handle disability insurance, investigate treatment options or meet with doctors. A health care poa is more extensive than a living will, which typically covers only the end of life.