Both delivery and handover refers to giving something to another person, but they are used in a different context.
Delivery is a legal term for giving or in other words turning over the possession of property, either physically or symbolically to another person. The property may either be real property, such as a building, or personal property, such as goods, money or a document.
Handover is the giving of control of or responsibility for something to someone else rather than a physical property. It can be used for handing over the responsibiliites arising from a job or any other activity.
