Technically neither the House of Commons nor the House of Lords has power to pass legislation without the approval of the monarch.
However, this royal seal of approval, the Royal Assent, cannot in practice be withheld and there are now no circumstances in which the monarch could prevent an act being passed.
Similarly the prime minister must seek the monarch's permission to form a government and to dissolve a Parliament.
This would normally be granted as a matter of formality but some constitutional writers have speculated on circumstances in which the monarch could, perhaps, reasonably refuse to comply, especially with the latter request.
The monarch - or a representative - is only personally present in Parliament for the annual state opening at which the Queen's (or King's) Speech sets out the government's aims and objectives for legislation in the coming session.