Press the Power button and Volume Down button at the same time
Release both buttons quickly
If that does not work, swipe the edge of your hand across the screen from right to left or left to right
If Palm swipe is not enabled, go to Settings > Advanced features > Motions and gestures > Palm swipe to capture and turn it on
Use the S Pen Air Command and tap Screen write on supported Samsung devices
Use the Assistant menu if enabled in Accessibility settings
Open the screenshot from the notification bar or Gallery after capturing it