Half bridge and full bridge PWM on a PIC ECCP are means of driving a half-bridge or full H-bridge, typically for motor control. These allow either 2 or 4 outputs to control each of the switches in your half (2) or full (4) bridge. It also allows you to insert dead-time between the switching of the different switches so that you do not get shoot-though, which is when the top and bottom switches of a half bridge are both on at the same time.
The waveforms should be there in the datasheet.
Bob