おはよう [ohayo-] is the greeting used before noon. But some people use it in the afternoon or even at night when they see their coworkers for the first time that day.
おはよう [ohayo-] ⇒ Good morning / Hi
(It is used between friends and family members.)
おはようございます [ohayo-gozaimasu] ⇒ Good morning / Hi
(It is used between less intimate acquaintances.)
Be sure to try it♡