Ionic bond is a type of bonds that results from transfers of electrons from one atom to another. This types of bond is formed between metals and non metals.
Metals lose electrons to form cations (positively charged ion) and non metals gain electrons forming anions, negatively charged ion.
For instance; between sodium and chlorine element; sodium donates a single electron to attain a stable configuration while chlorine gains an electron to achieve stable configuration, thus forming an ionic compound sodium chloride.