This is cover that pays out on death. Some plans pay upon earlier confirmation of a terminal illness where the prognosis is death within 12 months. It can pay out as a lump sum, or as income for a set period.
Cover can last for a set term called Term Assurance, or can last throughout life, called Whole of Life.
The amount of cover can remain the same or increase / decrease annually. Level term assurance stays the same throughout. Decreasing cover is sometimes used to cover a reducing debt, such as a repayment mortgage and usually assumes a given interest rate.
Provided your mortgage rates don’t exceed that rate, then the cover should reduce at around the same rate as the mortgage.
The amount you pay is called the premium. It can either be guaranteed not to change, or it can be reviewable. Reviewable cover normally changes based on the claims experience of the life assurance company.