require("xmlapi.php"); // this can be downlaoded from https://github.com/CpanelInc/xmlapi-php/blob/master/xmlapi.php
$xmlapi = new xmlapi("your cpanel domain");   
$xmlapi->set_port( 2083 );   
$xmlapi->password_auth($opts['user'],$opts['pass']);    
$xmlapi->set_debug(0);//output actions in the error log 1 for true and 0 false 

$cpaneluser=$opts['user'];
$databasename="something";
$databaseuser="else";
$databasepass=$opts['pass'];

//create database    
$createdb = $xmlapi->api1_query($cpaneluser, "Mysql", "adddb", array($databasename));   
//create user 
$usr = $xmlapi->api1_query($cpaneluser, "Mysql", "adduser", array($databaseuser, $databasepass));   
//add user 
$addusr = $xmlapi->api1_query($cpaneluser, "Mysql", "adduserdb", array("".$cpaneluser."_".$databasename."", "".$cpaneluser."_".$databaseuser."", 'all'));

上面的代码对我有用！
需要确保您使用的是cpanel用户/密码而不是root用户，并且还要使用端口2083

The above code worked for me! Need to make sure that you are using a cpanel user/pass not root and also that you are using port 2083