ROM Hack Question How can you edit game start items?

[Eliknaffo]

I wanted to know if it’s possible to edit the start of the game items you have in your bag in Pokémon sword and shield (even if I need to edit code) I just don’t really know where to start or where to go.

Any help on that matter will be great.

I want to make a completely modded game and that’s one of the only things I couldn’t figure out

thanks in advance