On our cPanel hosting services, the primary domain name’s directory will always be public_html/ and this cannot be changed in the Domains section of cPanel (like how you can change this for add-on domains and sub-domains). However, you can add the following code to your site’s .htaccess file to nominate a different folder for your site to load from. PLEASE NOTE: This method is for advanced users and is not recommended if you are not familiar with modifying your website’s .htaccess file.
# START Change Document Root
RewriteEngine on
RewriteCond %{HTTP_HOST} ^yourdomaingoeshere.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^www.yourdomaingoeshere.com$ 
RewriteCond %{REQUEST_URI} !nominatedfoldername/
RewriteRule (.*) /nominatedfoldername/$1 [L]
# END Change Document Root
In this example, change “yourdomaingoeshere.com” to your website’s domain name, and “nominatedfoldername” to your website’s nominated document root path.