Summary
Press Power + Volume Up at the same time to capture your screen; the image is saved automatically to your Gallery.
Steps
Navigate to the screen you want to capture
Press and briefly hold Power + Volume Up together
Release when you see a capture animation or hear a shutter sound
Open Gallery → Screenshots to view your image
Considerations
Timing issue: If the volume menu appears instead of a screenshot, press both buttons more simultaneously
During setup wizard or lock screen: Screenshots may be disabled on certain protected screens
Low storage: Screenshot will fail if device storage is full
Accessory keypad attached: Button combination remains the same
When to Contact Support
Create a support ticket if Power + Volume Up never captures a screenshot on any screen after repeated attempts.
What to Collect for Support
Whether you see a screenshot animation or sound when pressing the buttons
Whether the screenshot appears in Gallery → Screenshots
Current available storage on the device
Whether the issue occurs on all screens or only specific apps/screens
Your last system update