Ctrl + Alt + Something

On Windows 

		Those two shortcuts depend on the app you’re using—they’re not universal system-wide commands—but in many common contexts (especially web browsers and editors), they’re often tied to text formatting: Ctrl + Alt + U → usually underline text Ctrl + Alt + I → usually italicize text For example, in editors like Google Docs or some rich-text fields, italic (I) and underline (U) follow that pattern. Pressing Ctrl + Alt + Delete in Windows opens a secure system menu allowing you to lock the computer, switch users, sign out, change passwords, or launch the Task Manager to close frozen apps.   On Mac  The Mac equivalent to Ctrl+Alt+Delete is Command + Option + Escape
		This keyboard shortcut opens the Force Quit Applications window, allowing you to select and immediately close unresponsive applications.