#1For beginners and world champions alike: as black defend 1 e4 e5 and 1 d4 d5, as white open 1 e4.
If you are kind of new to openings then I suggest you to play London System as white because is pretty much all terrain (you can play it against most of black responses). You can also try the King's Indian Attack.
the one you play most often.
if you dont know what it is, randomly pick one and play it often.