The keyboard shortcut "Command + Z" is commonly used on Apple computers to undo the last action performed. This function is helpful in various applications, such as text editors, graphic design software, and spreadsheets, allowing users to quickly revert mistakes or changes they no longer want. When you press "Command + Z," the software typically restores the previous state of the document or project. This feature enhances productivity by enabling users to experiment without the fear of making irreversible errors, making it a fundamental tool for both casual and professional users.