Save message to file:

/etc/motd

And then restart sshd

$ sudo systemctl restart sshd

$ ssh [email protected]
Welcome to Ubuntu 16.04.6 LTS (GNU/Linux 2.6.32-042stab141.3 x86_64)
Documentation: https://help.ubuntu.com
Management: https://landscape.canonical.com
Support: https://ubuntu.com/advantage
Ubuntu 20.04 LTS is out, raising the bar on performance, security,
and optimisation for Intel, AMD, Nvidia, ARM64 and Z15 as well as
AWS, Azure and Google Cloud.
https://ubuntu.com/blog/ubuntu-20-04-lts-arrives

<<< contents of the /etc/motd file will go there>>>

Last login: Sat May 16 20:16:56 2020 from 37.30.54.65
root@host:~ $