Ctrl + W is a keyboard shortcut that usually closes what you’re currently working in. Exact behavior depends on the program and operating system.
Common behavior
In most web browsers (Chrome, Edge, Firefox, etc.), Ctrl + W closes the current tab; if it’s the only tab, it closes the browser window. In many applications like File Explorer or other programs with multiple documents or tabs, it closes the active document, tab, or window rather than quitting the whole app.
In Microsoft Office apps
In Word, Excel, PowerPoint, and similar Office programs, Ctrl + W closes the current document or file but typically leaves the application itself open. This is similar in effect to using the Close command from the File menu for just that document.