certbot configure
certbot certonly --webroot -w /var/www/html -d www.theflock.de -d theflock.de
Source: certbot.eff.org
certbot command
certbot certonly --webroot -w /var/www/example -d www.example.com -d example.com -w /var/www/other -d other.example.net -d another.other.example.net
Source: certbot.eff.org