Before editing, you must determine which software created the .sav file:
For specific games (e.g., Stardew Valley, Pokémon, Zelda ), search for a "Save Editor" specific to that title. These provide a user-friendly interface instead of raw code. How To Edit Active Sav File
Are you trying to change a (like money, level, or a variable)? Are you on PC, Console, or Mobile ? Before editing, you must determine which software created