Arrival, initial, intemediate, final and missed approach segments. Initial, final and missed approach always required.
Width depends on type of navigation aid/system
MOC 300m/1000ft arrival, initial 150m/500ft intermediate 75m/250ft final (90m/300ft if no FAF) 30m-50m/100-165ft missed approach for non-precision approaches.
Precision segments do not have a MOC as such, and are assessed differently.