Activating this trainer:
Press F1 at main menu.
Listen for 'Trainer Activated'.
Press desired hotkey. All hotkeys can be changed on the trainer.
NumPad1: Invincible / Ghost Mode
NumPad2: Freeze Timer
NumPad3: Change Score By 500
NumPad4: Change Rings By 500
NumPad5: Infinite Boost
Invincible / Ghost Mode: While active nothing will hurt you and you can run through enemies.
Unlock more trainer options including updates from here - Sonic Forces Trainer