mInstaller ( https://www.motionvfx.com/page/mInstaller.html ) is a free app that we've created to simplify the download and installation of the products you've purchased, as well as to give you control over your plugin licenses. You can log in to it using your MotionVFX account name (your e-mail) and password.
Once launched, it will stay dormant in the top right corner of your screen.
Installing and uninstalling products requires access to specific folders on your disk, so whenever you do that, you will be asked for your Mac's administrator password. This will occur only once per session (until you restart your Mac).