Livepatch is included in Ubuntu Pro (previously known as Ubuntu Advantage). The recommended way to install it is using the Ubuntu Pro client. The instructions below show how to enable livepatching and install the client. Instructions can also be found in this tutorial.
# Attach your personal or enterprise subscription from ubuntu.com/pro
$ sudo pro attach [TOKEN]
# Explicitly enable livepatch
$ sudo pro enable livepatch
This will install the livepatch client, and enroll the system to the Ubuntu livepatch service.