Like every Android device its possible to give your Meizu device a personal note.
Rooting varies depending on your Flyme version and firmware type. If you have a rootable firmware (A/G) you need to log into a Flyme account first. The next step is to enter the Settings and search under (Fingerprint) and security for the root options.
However, on Flyme 4 for example this process might look a bit different as the rooting option is hidden in the Flyme tab of the Settings.
Unfortunately the source for most Flyme devices is closed and therefore its hard to create proper custom roms. As of now faust93 & Moyster from XDA-Developers are the only ones to provide actual custom roms.