The same design can be bought in a click format and a glue-down format, and the two produce quite different quotes for the same room.
Click floats over an underlay, often one already attached to the board. It is quick, it is the cheaper fit, and it can be lifted again. It is also the format that tolerates a slightly imperfect subfloor better, because it is not bonded to it.
Glue-down is bonded to the subfloor, so it is quieter and firmer underfoot and does not move at the perimeter. It is the specification for a large open area or a commercial floor. It also needs a genuinely flat subfloor, because a glued floor telegraphs everything beneath it, and that preparation is the line that carries the extra cost rather than the adhesive.