Matthew, Mark and Luke are called “The Synoptic” gospels. That means “same eye.” They are based on the same events. John also overlaps, being a gospel, but it also has many different stories.
Further, Matthew was written to the Jews, and Luke was written to one Theophylus, a lover of God. Luke was Greek, so he uses much more difficult Greek, and reflects a Greek outlook. Mark is much simpler and more basic. Finally John is thought to have been written later than the other three gospels. It also uses the word, “signs” for Jesus miracles.
So, different audience is another factor. It is good to look at the life of Jesus from four different perspectives. Of course, other books in both the OT & the NT add to our knowledge of Jesus, too.