C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\savegames\[User ID]\420
Example (conceptual; no offsets given)
Tools like Horizon allow players to move their save to a USB drive and open it on a PC to edit modifiers. Far Cry 4 Save Editor
Always copy your original save folder to a safe location before editing to prevent data loss. Run Editor: Launch your chosen editor (or use a trainer like Far Cry 4 Save Editor