The directory that your web server pulls data from will be defined by your VirtualHost (Apache) or by a Server Block (NGINX).
If you're using Apache, your VirtualHost files are stored in:
If you're using NGINX, your Server Block files are stored in:
For Apache, you'd want to change the
For NGINX, you'd want to change the
So, for example, if you setup
domain.com (example domain) to point to your Droplet, you'd modify one one of the above directives that corresponds to your domain and change the current path that's set to the one you'd prefer to use.
By default, both Apache and NGINX setup the default configurations to use
/var/www/html, so you would change to that your preferred path where your content is stored.
Once the changes have been made, and the file has been saved, you'd restart the web server.
service apache2 restart
service nginx restart