Four times in the book of Revelation the Lord Jesus or God identifies himself as “the Alpha and the Omega”: the beginning and the end or the first and the last, depending on your translation. This is not a title men have given him but a name by which he chooses to make himself known. It’s a reminder of the truth boldly stated numerous times throughout the New Testament (and probably not well understood prior to that time) that the Word was in the beginning with God and nothing at all was made without his participation.
The Son was personally active in the beginning, and he will be personally active again in the end. The title means more, of course, but that is certainly one implication.