In this post I am going to explain how to get customer details by id in PrestaShop 1.7.

// Your customer id
$id_customer = 4;

// Load customer object
$customer = new Customer((int) $id_customer);

// Validate customer object
if (Validate::isLoadedObject($customer)) {
	
	// Get Customer First Name
	echo $customer->firstname;
	
	// Get Customer Last Name
	echo $customer->lastname;
	
	// Get Customer Email
	echo $customer->email;
	
	// Print Customer Object
	echo "<pre>";
	print_r($customer);
	echo "</pre>";
}