Malleability is a physical property of matter, usually metals. This property usually applies to the family groups 1 to 12 on the Modern Periodic Table of Elements. It is the ability of a solid to bend or be hammered into other shapes without breaking. Examples of malleable metals are gold, iron, aluminum, copper (to a degree) and lead.
Malleability is the ability of a metal to be hammered into thin sheets. Gold and silver are highly malleable. When a piece of hot iron is hammered it takes the shape of a sheet. It is not observed in non-metals. Aluminium foil is one example of a malleable metal. Non-malleable metals will break apart when struck by a hammer such as tin.