I have uploaded a file to the public_html directory. What do I do next to publish the page? How can I use index.php instead of index.html for my site ?

Once a file is uploaded to public_html, it will be visible at your domain. If you upload a file called pets.html to public_html, it will be visible at http://www.yourdomain.com/pets.html.

Files called index.* ( index.html, index.htm, index.php) will be shown at http://www.yourdomain.com

If you remove index.html, other files with index.* will show up in its place. So, if index.php is the only file named index.* in public_html, it will show.

Alternatively, you can create a file called .htaccess containing this line in your public_html directory:

DirectoryIndex index.php

Make sure to remove that line from .htaccess if you no longer wish to see index.php when viewing your website.

If an HTML file is located in public_html and is not visible at your domain, make sure that it has 644 permissions and is owned by your username.