How to enable root user on linux server
login to your server with user name provided by your hosting company, usually it’s ubuntu or linux
After success full login use this command to set password for root
sudo passwd -u root
After that you need to enter desired password for root userAt this stage you can login via root user but not with ssh for enable root user login via ssh you should do one more step
Use this command to open ssh server config file
nano /etc/ssh/sshd_config
After that find this line
PermitRootLogin without-password
And change it to
PermitRootLogin yes
Then restart the ssh server with this command
systemctl restart sshd
now you can login to root user via ssh