Compared to the Uno, the Mega also comes complete with ... check out its pinout diagram documentation (found on the board's Arduino Store page). PWM pins in the diagram have the same tilde sign ...

it’s great for a quick-and-dirty circuit diagrams. Not exactly schematics, but [Duckman] has some Arduino pinout diagrams he made using ASCII-art. These could be useful when pasted into source ...

The Arduino Mega's PWM pins are digital output pins located ... If your board has no printed labels, check out its pinout diagram documentation (found on the board's Arduino Store page).