In Japan, there are basically two types of toilet: a Japanese-style (washiki) toilet with a bowl positioned at the height of the floor, which you squat over facing the hemispherical hood, and a seat-type Western-style (yoshiki) toilet. Most public buildings have restrooms equipped with these two types.
Some restrooms have slippers provided. In that case, you must change to slippers, but make sure to take them off when leaving. Occasionally, you may come across public restrooms without toiler papers, so it is advisable to always carry pocket-sized tissue papers with you, especially for women.