Push
Wide (wide-grip) push-ups shift emphasis to the outer fibers of the pectoralis major. Spreading the hands ~50% beyond shoulder width shortens the triceps' leverage so the chest does a larger share of the work.
From a plank, hands ~1.5× shoulder width, fingers slightly out for joint comfort. Lower with elbows opening to the sides (70-80° from the torso). Seek the largest comfortable range. Drive up hard.
Less triceps involvement; greater stretch tension in the chest on the way down—excellent for pectoral development.
Do not go excessively wide—that increases stress on the anterior shoulder capsule. If you feel discomfort, narrow the grip. Joint health always comes first.