Quote from Comprehensive Rules »
601.2a To propose the casting of a spell, a player first moves that card (or that copy of a card) from
where it is to the stack. It becomes the topmost object on the stack. It has all the characteristics
of the card (or the copy of a card) associated with it, and that player becomes its controller. The
spell remains on the stack until it’s countered, it resolves, or an effect moves it elsewhere.