by default the path /var/www/html is used for your websites.
If you want to add files to this location as user, you can create a group for this purpose.
Then add your user to this created group:
gpasswd -a [user] apache
replace "[user]" with your username.
Then set appropriate permissions to /var/www/html:
chgrp -R apache /var/www/html
chmod -R g+rw /var/www/html
If you open http://localhost/
in your browser it should show the page you just saw or the file /var/www/html/index.php if it exists (you can create and test it to see how it works).