TL;DR - nothing as LivePatch is not supported for Ubuntu 19.04 release.
I have Ubuntu MATE 19.04 LTS installed on VM and started Software & Updates (software-properties-gtk) to change repositories of it.
I was surprised that it has new Livepatch tab, it looks like
and says
Gnome Online Accounts is required to enable Livepatch.
or sometimes
Canonical Livepatch snap is not available
To fix this we hopefully need do the following:
snap install canonical-livepatch
sudo apt-get install gnome-online-accounts
and restart software-properties-gtk, but this will not work on Ubuntu 19.04 as it is not supported by Canonical Livepatch:
The service covers standard Canonical 64-bit x86 kernels on 14.04 LTS, 16.04 LTS, and 18.04 LTS. It dynamically monitors success rates, enabling us to reduce the risk of live kernel fixes by delivering them to a small initial group and then widening the footprint dynamically based on success.
So this Livepatch tab intended for future 20.04 LTS release.
This tab first appeared in 18.04 LTS.
For Ubuntu 18.04 LTS see How do I enable livepatch in ubuntu 18.04 lts?