You can go to the official site of OnyX, Titanium Software, to free install the right version on your Mac. But you can choose to donate as you like.
With the OnyX for Mac, you can handily repair permissions, rebuilt databases, re-organize system file structures, check and manage hard disk structures, and restore indexes. OnyX offers different versions for macOS Sonoma 12 or later, macOS Big Sur, macOS Catalina, macOS Mojave, macOS High Sierra, macOS Sierra, OS X El Capitan, OS X Yosemite, OS X Mavericks, and earlier Mac operating systems. OnyX for Mac provides you with a simple way to optimize your Mac operating system, check Mac hard disk's start-up volume, and quickly fix various errors that it may find. Moreover, it can clean tasks, manage various Mac data, delete caches, remove useless folders and files, configure parameters, and fix different Mac errors. OnyX is a well-known multi-function utility that mainly designed for verifying the Mac startup disk and the structure of macOS system files. OnyX for Mac Review - Pros and Cons of OnyX Mac Cleaner
