When it comes to vessel sink installations, there're two distinct types:
Recessed Installation
The recessed or below-counter installation offers increased basin stability. In this type of installation, the sink basin rests partially into the countertop. Also, it requires a large drain hole to make room for the basin.
Above-Counter Installation
The above-counter is the opposite of the recessed. The vessel sink rests entirely on the countertop. This installation requires a drain hole of 1 5/8" to 1 3/4" and no additional cutting of the vanity. If you want an option that's easy to clean, the above-counter mount is ideal since the countertop and sink basin is exposed.