Get order collection by order id in Magento 2?

Just Remove getCollection :-

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$orders = $objectManager->create('Magento\Sales\Model\Order')->load($oid);

echo $custLastName= $orders->getCustomerLastname();

The Following code will easily get Customer details, Billing, Shipping and order totals

  $orderId = 1222;
  $objectManager = \Magento\Framework\App\ObjectManager::getInstance(); 
  $order = $objectManager->create('\Magento\Sales\Model\OrderRepository')->get($orderId);

  /*get customer details*/

  $custLastName= $orders->getCustomerLastname();
  $custFirsrName= $orders->getCustomerFirstname();
  $ipaddress=$order->getRemoteIp();
  $customer_email=$order->getCustomerEmail();
  $customerid=$order->getCustomerId();

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

  /* get shipping details */

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

 /* get  total */

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