Focus Assist mode in Windows 11 allows users to block notifications and stay focused on one task. It has three modes: blocking all notifications, blocking only from apps you don't specify, and a custom schedule. Users can enable Focus Assist mode to avoid distractions from other apps and notifications while working concentrated on one task or project. The Quick Task Switcher feature using Alt+Tab allows quick switching between open apps, but can also be distracting, so Focus Assist mode prevents this while keeping a user focused on one application at a time.