The Iraqi constitution is a hodge-podge of conflicting laws. Maybe the resignation must be approved by parlament, maybe not. Forming a caretaker government and what powers it has is a question.
Usually a caretaker cannot add or remove anything . Even the new budget would be in limbo .. Here in the US the house would enact a continuing resolution which allows the caretaker limited powers and anything else must be handled thru congress. Fortunately the party with a majority can get most things done. Iraq does not have a 2 party system so there is no established majority.