Your Power of Attorney, or POA is a document that quite literally, 'empowers' someone to act for you. They don't actually need to be an attorney (lawyer).
A power of attorney for finance empowers someone to manage your financial affairs. This is important because if you were incapacitated for any reason, such as if you out of the country, were in a car accident or had early-onset dementia, you would need someone to look after everything.
We recommend WillFul, where you can prepare your power of attorney in a number of provinces with guidance through each step.
If you wait until you need it, it'll be too late to get it.