Galaxy Tab S4: Set Up a Screen Lock
To Set Up a Screen Lock Navigate to Apps screen → Touch Settings → Touch Lock screen → Touch Screen lock type (For this example, touch PIN) → Enter a PIN → Touch CONTINUE → Re-enter the PIN → Touch OK → Set display options for notifications → Touch DONE.
Pictorial representation of the above settings are as follows :
Note: Increase your tablet's security by setting up a screen lock. Pattern, PIN, or Password locks provide better protection than Swipe lock and are all configured from the Screen lock type menu.