You can customize window borders and shadows on Windows 10 by following these steps:

  1. Open the Settings app.
  2. Click on Personalization.
  3. Click on Colors.
  4. Scroll down to the Window borders section and select the color that you want for your window borders.
  5. To change the thickness of the window borders, use the Thickness slider.
  6. To enable or disable shadows for your window borders, toggle the switch next to Show shadows under windows.
  7. To change the color of the shadows, use the Color selector.

You can also customize window borders and shadows on Windows 11 by following these steps:

  1. Open the Settings app.
  2. Click on Personalization.
  3. Click on Colors.
  4. Scroll down to the Window borders section and select the color that you want for your window borders.
  5. To change the thickness of the window borders, use the Thickness slider.
  6. To enable or disable shadows for your window borders, toggle the switch next to Show shadows under windows.
  7. To change the color of the shadows, use the Color selector.

In addition to the steps above, you can also use a third-party app to customize window borders and shadows on Windows. Some popular third-party apps for customizing window borders and shadows on Windows include:

  • Winaero Tweaker: Winaero Tweaker is a free and open-source app that allows you to customize various aspects of Windows, including window borders and shadows.
    Winaero Tweaker app
  • Ultimate Windows Tweaker: Ultimate Windows Tweaker is another free and open-source app that allows you to customize various aspects of Windows, including window borders and shadows.
    Ultimate Windows Tweaker app
  • WindowBlinds: WindowBlinds is a paid app that allows you to customize the look and feel of Windows, including window borders and shadows.
    WindowBlinds app

Whichever method you choose, you can customize window borders and shadows on Windows to create a look that you like.