If you are installing a laminate floor and you aren’t going to remove the baseboard, you will need to span the gap with molding. The gap will be small but unsightly so you need to cover it. Quarter-round molding is small and is the customary molding to use, but really , any molding you like will work, so long as it covers the gap. Quarter round is simply a 90-degree angle with a rounded surface connecting the points (think of a circle cut into quadrants and that is the profile).
Installing the molding goes quickly with a nail gun and a power miter saw. I would start on a long wall and start installing the trim. It’s easy to mark the wood studs with a stud sensor, and then place a piece of painters tape at that location. So when you go to nail the trim, you know exactly where the studs are and you don’t have to waste any time. When you come to a corner, miter the corners and place a nail in close proximity to the corner on each piece. Press the nail gun into the corner on the trim to hold it in its final place and then squeeze the trigger.
When you are done, you will have the original baseboard with a small piece of quarter round trim along the bottom of it all around the perimeter.