Control + A (or Ctrl + A) is a keyboard shortcut that is used to select all the text or content in a document or text editor.
When you press the Control key and the "A" key at the same time, it selects all the text, images, and other content that is visible on the screen. This can be very useful when you need to quickly copy, cut, or delete all the content in a document, or when you want to apply formatting or style changes to the entire document.
Control + A is supported by most operating systems and applications, including Windows, Mac OS, Linux, and various text editors, word processors, and web browsers. The specific action performed when you press Control + A can vary depending on the application or context, but in most cases, it will select all the visible content on the screen.