AddMachineIdField.php

function my_pmprorh_init() {
	// Don't break if Register Helper is not loaded.
	if ( ! function_exists( 'pmprorh_add_registration_field' ) ) {
		return false;
	}

	// Define the fields.
	$fields = array();
	$fields[] = new PMProRH_Field(
		'machineId',						// input name, will also be used as meta key
		'text',								// type of field
		array(
			'label'		=> 'Machine Id',	// custom field label
			'size'		=> 30,				// input size
			'class'		=> 'company',		// custom class
			'profile'	=> true,			// show in user profile
			'required'	=> false,			// make this field required
		)
	);

	// Add the fields into a new pmprorh_registration_fields
	foreach ( $fields as $field ) {
		pmprorh_add_registration_field(
			'pmprorh_registration_fields',	// location on checkout page
			$field							// PMProRH_Field object
		);
	}
	
	function my_pmpro_add_memberslist_col_machineId( $columns ) {
		$columns['machineId'] = 'Machine Id';
		return $columns;
	}
	
	add_filter( 'pmpro_manage_memberslist_columns', 'my_pmpro_add_memberslist_col_machineId' );
	
	function my_pmpro_fill_memberslist_col_machineId( $colname, $user_id ) {
		if ( 'machineId' === $colname ) {
			echo esc_html( get_user_meta( $user_id, 'machineId', true ) );
		}
	}
	add_filter( 'pmpro_manage_memberslist_custom_column', 'my_pmpro_fill_memberslist_col_machineId', 10, 2 );

}
add_action( 'init', 'my_pmprorh_init' );