Never save the game with toggled on if you plan to later play online or legitimately. Some trainers write permanent values to your save file. Instead:
When looking for a trainer, it is vital to download from reputable sources. Because trainers inject code into a running process, your antivirus software will likely flag them as a "false positive." Always ensure you are downloading from well-known community sites. To use the trainer, you typically launch the game first, then ALT+TAB out to run the trainer as an administrator. Once both are running, you can use hotkeys (usually Numpad keys) to toggle your desired cheats. A Note on Fair Play
A: Only if you go online with cheats active or if the trainer modifies the executable itself (rather than just memory). For absolute safety, launch Ubisoft Connect in offline mode before starting the game.