Metamorphosis means changing into another form. Complete metamorphosis has a pupa stage. The pupa is also called a chrysalis (butterflies) or a cocoon (moths). The larva stage looks very different from the adult. Butterfly larva are called caterpillars. Winged insects that undergo complete metamorphosis get their wings in the adult stage.
More examples of complete metamorphosis: Ants Wasps Flies Beetles Antlions
Look up the life cycle of these insects to learn more!
Incomplete metamorphosis is also called gradual metamorphosis. There is a nymph stage. The nymph looks like a smaller version of the adult. The nymph may have wings, but the wings will not be fully developed until the adult stage. The adult stage is also when the insect is capable of reproduction.
More examples of incomplete metamorphosis: Praying mantids Cockroaches Termites Assassin bugs Aphids Cicadas