A "screen-off memo" is a feature found on some smartphones that allows users to jot down notes or reminders without needing to unlock their device. This function is particularly useful for quickly capturing thoughts or ideas when the screen is off, saving time and effort. Typically, users can activate this feature by removing the device from their pocket or tapping the screen. The memo can be written using a stylus or finger, and it is often saved automatically for later reference. This feature enhances productivity by making note-taking more convenient and accessible.