Hi , it's up under the large nut on the bottom of the motor , it's a conical wire screen , you might as well change the oil at the same time as it will pour out once the nut is removed , It doesn't use must oil in the sump so a 1 liter bottle of 10/40 (mobil i use ) will be more that enough ,
More neglected is the EP 80 / 90 gearbox oil in the small reduction gearbox in the very end of the transmission , near the rear brake adjuster , i would always change that too as sometimes it is NEVER done from new , you only need a 100 ml tube of this , all Kymco scooters have this and most are neglected , there are many bearings and expensive gears in there , it's a sound investment to do this ,
Hope that helps