Since the Parallels provider is a Vagrant plugin, installing it is easy:
$ vagrant plugin install vagrant-parallels
The Vagrant plugin installer will automatically download and install
- Vagrant v1.8 or higher (there is a known issue with Vagrant v1.9.5: GH-297)
- Parallels Desktop for Mac version 10 or higher
Only Pro and Business editions of Parallels Desktop for Mac can be used with this Vagrant provider.