Hello
The feature you’re referring to is a design element of Windows, and according to a Microsoft Community post, it’s not possible to disable this feature through the settings. The active window is highlighted to distinguish it from other open windows.
However, if you’re referring to a different setting where windows are automatically activated and brought to the front when you hover over them with your mouse, you can disable this feature by following these steps:
Press the Windows key + R to open the Run dialog box.
Type Control and hit Enter to open the Control Panel.
Open Ease of Access Centre.
Click on Make the Mouse Easier to Use.
Uncheck Activate Window by hovering over it with the mouse.
Click Apply then OK.