Level or Decreasing
With level cover the lump sum paid out at claim stays the same over the period you’re insured for. You choose how long you want to be insured for and how much to receive.
With decreasing cover the lump sum paid out at claim reduces over time, usually in line with your repayment mortgage.
Whatever kind of mortgage you have, bear in mind that if the full amount of your mortgage isn’t protected, then the lump sum paid out may not be enough to pay off your mortgage in full, should anything happen to you.