Right-click the desktop and open Display settings
Select the monitor you want to rotate
Find Display orientation
Choose Portrait, Portrait (flipped), Landscape, or Landscape (flipped)
Select Landscape (flipped) to turn the screen upside down
Click Apply
Confirm the change if prompted
On Windows, you can also use the graphics control panel to rotate the display
On some monitors, use the built-in menu buttons to check for rotation settings
On macOS, open System Settings, go to Displays, and choose the rotation option if available