Where do you enter the codes in Pokemon LeafGreen?

Answer 1

I'm not 100% sure on what codes you're talking about, but if it's the ones I'm thinking of, then you need something called GameShark. Gameshark is a range of video game cheat cartidges, in other words, you use game shark and enter in the right codes so that you can hack into the game and you can edit the game.

As for the codes, you can get some here: http://www.supercheats.com/gameboyadvance/pokemonleafgreencodes.htm but this requires you to create an account.

They have code like easier catch rates in the safari zone, codes to get sprites of Pokemon wherever you want to put them and on YouTube they show videos of games that have been hacked into and they can walk through walls and stuff XS

I've never actually used it myself cause I think it's waste of time hacking into a perfectly good game, but if you're into that sort of thing, then happy hacking!!