An Annuity is a contract where you pay a lump sum premium to an insurance company in return for period payments for the rest of your life or up to an agreed number of years, the latter ending when you die.
It is a life policy in reverse. It converts capital to income.
A standard annuity will not have any special tax concessions for being used to pay long term care. The benefits may be taxable
This is not a special Long Term Care product.