(Steam version)

I seen some questions around on other posts about how to do them, but no one responded with an answer.

Now updated to match the manual here.

Thanks /u/rh_underhill !

Picture here with all the keys, descriptions, and icons that display (taken from the manual).

F1 = High Speed Mode - Speed up certain parts of the game.

F2 = Battle Assistance - Grants you an always full ATB gauge, as well as full HP and MP. Trance is also always available.

F3 = 9999 - Attacks will deal 9999 damage.

F4 = Safe Travel - Eliminates random encounters with enemies. This does not include event battles. Please note that by enabling this feature, you will not encounter friendly monsters.

F5-F7 can be found through the Config menu at the bottom as well, but there are hot keys that you can press if you don't want to go in there.

F5 - Master Abilities - Abilities will be mastered immediately after acquiring their associated items.

F6 - Level and Magic Stones Max - Your level and number of magic stones will be set to maximum.

F7 - Gil Max - Grants you the maximum limit of gil.

You can also do these actions with a controller when the game is paused. Please refer to this picture from the manual to figure out which button is which since others may have different button configurations.