How do you downgrade a mac system?

To downgrade a Mac system, you typically need to back up your data using Time Machine or another backup solution, as the process will erase your current installation. Next, create a bootable USB drive with the desired macOS version using the macOS installer. Restart your Mac while holding the Option key to access the boot menu, select the USB drive, and follow the on-screen instructions to install the older macOS. After the installation, you can restore your data from the backup if needed.