WordPress uses wp_insert_user to insert user in to the database. Or this function can be used to update the user information programmatically. WordPress Create User Programmatically using this code snippet.

Create User Programmatically WordPress

Usage:

<?php wp_insert_user( $userdata ) ?> 

Parameters :

$userdata it is an array with all the information about the user.

Field NameDescription
IDAn integer that will be used for updating an existing user.
user_passA string that contains the plain text password for the user.
user_loginA string that contains the users username for logging in.
user_nicenameA string that contains a nicer looking name for the user.
user_urlA string containing the users URL for the users web site.
user_emailA string containing the users email address.
display_nameA string that will be shown on the site. Defaults to users username. It is likely that you will want to change this, for both appearance and security through obscurity (that is if you dont use and delete the default admin user).
nicknameThe users nickname, defaults to the users username.
first_nameThe users first name.
last_nameThe users last name.
descriptionA string containing content about the user.
rich_editingA string for whether to enable the rich editor or not. False if not empty.
user_registeredThe date the user registered. Format is Y-m-d H:i:s.
roleA string used to set the users role.
jabberUsers Jabber account.
aim Users AOL IM account.
yim Users Yahoo IM account.

Example:

ADD User

<?php
$useri
wp_insert_user( array ('user_url' => $website) ) ;
?>