To disable the ssh motd (message of the day) welcome message on Ubuntu Linux, you can edit the /etc/ssh/sshd_config file and set the PrintMotd option to no.
Here is an example of how to disable the ssh motd welcome message:
/etc/ssh/sshd_config file in a text editor:sudo nano /etc/ssh/sshd_config
PrintMotd option in the file and set it to no:PrintMotd no
Save the file and exit the text editor.
Restart the ssh daemon to apply the changes:
sudo systemctl restart ssh
This will disable the ssh motd welcome message, and it will no longer be displayed when you log in to the system via ssh.
Note that the ssh motd welcome message is not the only message that is displayed when you log in to the system via ssh. There may be other messages, such as the /etc/motd message or the /etc/issue message, that are still displayed. To disable these messages, you will need to edit the appropriate configuration files or remove the files altogether.