Legislation adopted by parliament requires the assent of the Head of State
In some countries, the Constitution foresees that legislation adopted by parliament must be signed into law by the Head of State. If so, the Head of State may, for example, have the power to veto the legislation, return it to parliament, or submit it to another body such as a constitutional court.
Source
Legal documents that stipulate parliament's role.
Sections 55 to 57 of the Constitution Act, 1867 deal with the granting of Royal Assent by the Governor General, and with the circumstances in which Assent can be withheld. More recently, the Royal Assent Act (S.C. 2002, c. 15) was passed to provide an alternative to the formal Royal Assent process formerly used in the Canadian Parliament, so that Royal Assent can be signified by written declaration. Technically the Head of State could refuse to give a bill Royal Assent, however by convention the Governor General does not refuse and always acts on the advice of the Prime Minister and Parliament.