The "Select All" command is a function commonly found in software applications that allows users to highlight all the content within a document or interface. This command is typically executed by pressing Ctrl + A on Windows or Command + A on macOS. It is useful for quickly selecting text, images, or other elements for editing, copying, or formatting. Once all items are selected, users can perform various actions, such as copying the content to the clipboard or deleting it. This command enhances efficiency by eliminating the need to manually click and drag over each item, making it a valuable tool for productivity in digital environments.