<?php

namespace MyPluginObserver;

use MagentoFrameworkEventObserverInterface;

class LogAddMessage implements ObserverInterface {

protected $_logger;

public function __construct(
PsrLogLoggerInterface $logger, array $data = []
) {
    $this->_logger = $logger;
}

public function execute(MagentoFrameworkEventObserver $observer) {
    $order = $observer->getEvent()->getOrder();
    $order_id = $order->getID();
    $order_number = $order->getIncrementId();
    foreach ($order->getAllItems() as $item) {
            $ProdustIds[] = $item->getProductId();
            $ProdustSku[] = $item->getSku();
            $proName[] = $item->getName(); //product name
            $this->_logger->addDebug('Item Name: ' . $item->getName() . 'Item ID: ' . $item->getProductId());
        }
        $proName = json_encode($proName);
        $ProdustSku = json_encode($ProdustSku);
        $customerId = $order->getCustomerId();
        $objectManager = MagentoFrameworkAppObjectManager::getInstance();
        $customer = $objectManager->create('MagentoCustomerModelCustomer')->load($customer);
        $address = $observer->getShippingAddress();
        $address = json_encode($address);
        $name = $customer->getName(); //customer name
        $this->_logger->addDebug('Order ID: ' . $order_id . ', Products: ' . $proName . ', SKU: ' . $ProdustSku . ', Customer ID: ' . $customerId . ', Customer Name: ' . $name . 'Address: ' . $address);
    }

}

$customer = $objectManager->create('MagentoCustomerModelCustomer')->load($customer);

$customer = $objectManager->create('MagentoCustomerModelCustomer')->load($customerId);

$addressObj = $order->getBillingAddress();

echo '<pre>'; print_r($addressObj);

$addressObj = $order->getBillingAddress();
$to = $addressObj->getTelephone();

public function __construct
 (
  MagentoSalesModelOrder $order
 )
 $this->order = $order;
 public function execute(MagentoFrameworkEventObserver $observer)
    {
      $orderId = $observer->getEvent()->getOrderIds();
      $order = $this->order->load($orderId);
      $orderid=$order->getEntityId();

      $billingaddress=$order->getBillingAddress();
      $billingcity=$billingaddress->getCity();
      $billingstreet=$billingaddress->getStreet();
      $billingpostcode=$billingaddress->getPostcode();
      $billingtelephone=$billingaddress->getTelephone();
      $billingstate_code=$billingaddress->getRegionCode();

      $shippingaddress=$order->getShippingAddress();
      $shippingcity=$shippingaddress->getCity();
      $shippingstreet=$shippingaddress->getStreet();
      $shippingpostcode=$shippingaddress->getPostcode();
      $shippingtelephone=$shippingaddress->getTelephone();
      $shippingstate_code=$shippingaddress->getRegionCode();

      $tax_amount=$order->getTaxAmount();
      $total=$order->getGrandTotal();