Samsung Good Lock is a free official app available on the Galaxy Store that lets you deeply customize One UI on any Samsung Galaxy device running One UI 3.0 and above. It is divided into two sections — Life Up for functional changes and Make Up for visual customization. Key modules include LockStar for lock screen redesign, HomeUp for home screen control, QuickStar for notification panel customization, MultiStar for multitasking, SoundAssistant for per-app volume control, Keys Cafe for keyboard design, and Theme Park for system-wide color theming. Good Lock is free, works on phones and tablets, and is fully compatible with One UI 8.5 in 2026.