Difference between external and internal switch mosfet?
They're not MOSFETs as such they're listed as PMICs which are power management ICs. They can include things like switching power supply and H Bridge controllers. The internal ones have the power switching MOSFET(s) built into the chip whereas with external you need to provide your own.

The internal ones lower the part count but an advantage to external MOSFET devices is that you can select the most appropriate (including larger) MOSFETs for your application. In the latter case the MOSFET can also have additional heatsinking provided.