I know for save editor website and i used it before but with that you can just edit amount of items and i think HP and that's it, but i want to edit the level of my character and also the companion.
You'd better ask here: RPG Maker Save Editors
You should specify the game engine, because the save format depends on it.
As for the level of your characters, in RPG Maker it depends on their XPs (if I am not mistaken): that's what you need to change.