Looking for logging into the Ubuntu As Www-data site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Ubuntu As Www-data site. After that you can login as usual with your login credentials.
https://ubuntuforums.org/showthread.php?t=2280551
https://unix.stackexchange.com/questions/327436/cannot-run-command-as-www-data-using-su
https://askubuntu.com/questions/702060/how-to-give-permissions-to-www-data-to-log-in-with-ssh
https://serverfault.com/questions/388016/bash-scripting-su-to-www-data-for-single-command
https://serverfault.com/questions/388016/bash-scripting-su-to-www-data-for-single-command/566457
http://techamad.blogspot.com/2015/04/login-as-www-data-apache-user-in-ubuntu.html
https://www.digitalocean.com/community/questions/should-i-enable-a-password-for-user-www-data
http://programster.blogspot.com/2014/05/ubuntu-1404-allow-login-as-www-data-user.html
https://franciskim.co/switch-user-to-www-data-on-aws-ec2-ubuntu/
https://stackoverflow.com/questions/19712778/apache-user-account-passwordless-access-to-the-server-ubuntu
https://superuser.com/questions/162712/how-can-i-check-whether-a-user-has-login-permissions-on-ubuntu
https://www.cyberciti.biz/faq/ubuntu-add-user-to-group-www-data/
https://www.webhosterwissen.de/know-how/eigener-webserver-nginx/tutorial-nginx-php-mysql-auf-ubuntu-18-04-installieren/