An absolute monarchy could be a government within which a monarch acts because the head of state, however, has powers that are restricted by a constitution. The monarch has unbridled powers and acts as each head of state and head of the presidency.
Therefore, the main difference between a limited and absolute monarchy is the amount of power that the monarch has. Several countries that after had absolute monarchies became restricted monarchies.
Power is invested solely in between both type of governments and they are both heads of state and government.
For example, Saudi Arabia, Brunei, Swaziland and the Vatican City are ruled by one person and are called Absolute monarchies.