$address01->setCountry("US");
$getTaxRequest->setOriginAddress($address01);
//
//Destination Address
$address02 = new Address();
$address02->setLine1("118 N Clark St");
$address02->setLine2("Suite 100");
$address02->setLine2("ATTN Accounts Payable");
$address02->setCity("Chicago");
$address02->setRegion("IL");
$address02->setPostalCode("60602-1304");
$address02->setCountry("US");
$getTaxRequest->setDestinationAddress($address02);
//
//Third Address
$address03 = new Address();
$address03->setLine1("100 Ravine Lane");
$address03->setLine2("Suite 100");
$address03->setLine2("");
$address03->setCity("Bainbridge Island");
$address03->setRegion("WA");
$address03->setPostalCode("98110");
$address03->setCountry("US");
//Coming Soon
//$address03->setLatitude("47.626930");
//$address03->setLongitude("-122.521004");
$getTaxRequest->setAddressCode($address03);
//
//Set DocumentLevel Addresses
$getTaxRequest->setOriginAddress($address01);
$getTaxRequest->setDestinationAddress($address02);
<?php

require 'vendor/autoload.php';
//Authentication
//TODO: Modify the account and license key values
//      contained set in Credentials.php with your own
require 'Credentials.php';
use AvaTax\Address;
use AvaTax\AddressServiceSoap;
use AvaTax\TextCase;
use AvaTax\ValidateRequest;
use AvaTax\SeverityLevel;
$addressSvc = new AddressServiceSoap('Development');
try {
    $address = new Address();
    $address->setLine1("118 N Clark St");
    $address->setLine2("");
    $address->setLine3("");
    $address->setCity("Chicago");
    $address->setRegion("IL");
    $address->setPostalCode("60602");
    $textCase = TextCase::$Mixed;
    $coordinates = 1;
    //Request
    $validateRequest = new ValidateRequest($address, $textCase ? $textCase : TextCase::$Default, $coordinates);
    $validateResult = $addressSvc->Validate($validateRequest);
    //Results
    echo "\n" . 'Validate ResultCode is: ' . $validateResult->getResultCode() . "\n";
    if ($validateResult->getResultCode() != SeverityLevel::$Success) {
        foreach ($validateResult->getMessages() as $message) {
            echo $message->getName() . ": " . $message->getSummary() . "\n";