It varies based on the laser power, but 0.12 to 0.18 mm is typical.
I usually de-focus slightly for engraving as that expands the beam slightly (at the expense of maximum power) and use 0.18 which overlaps just enough to not get lines in the finished product.
The cutting kerf will depend on the material, but probably towards the smaller size, however the heat affected zone of the kerf will be much larger and can result in charring along the kerf.