Add Custom field in User Profile

add_action( 'show_user_profile', 'my_show_extra_profile_fields' );
add_action( 'edit_user_profile', 'my_show_extra_profile_fields' );

function my_show_extra_profile_fields( $user ) { ?>

Extra profile information

Twitterlabel>	Please enter your Twitter username.

//------------------------------------------------------------------------------------------saving fields----------------------------------------------------
add_action( 'personal_options_update', 'my_save_extra_profile_fields' );
add_action( 'edit_user_profile_update', 'my_save_extra_profile_fields' );

function my_save_extra_profile_fields( $user_id ) {

if ( !current_user_can( 'edit_user', $user_id ) )
return false;

/* Copy and paste this line for additional fields. Make sure to change 'twitter' to the field ID. */
update_usermeta( $user_id, 'twitter', $_POST['twitter'] );
}
//-----------------------------------------------------------------------------------------usage-----------------------------------------------------------------
//the_author_meta( $meta_key, $user_id );
?>