set ajax response in php variable - php

Question

I am trying to set json response in php variable.After success response my html data is printed in div.
Any Idea How to upload This in a Php variable. it's any idea where I can store this in a session or cookies.
$('#pincode').on('change', function() {
//const formData = $('#formid').serializeArray();
var address = $("input[name=address]").val();
var pincode= $("input[name=pincode]").val();
var price = $("input[name=price]").val();
var city = $("input[name=city]").val();
var country =$('#country').val();
var state = $('#state').val();
//var state =$(this).val();
//console.log(formData);
$.ajaxSetup({
headers: {
'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
}
});
$.ajax({
type:'POST',
data:{address:address, pincode:pincode, price:price,country:country,state:state,city:city},
url:'./ava',
dataType: "text",
success:function(data){
$('#gettax').html(data);
//alert(res);
},
error: function (err) {
console.log(err);
alert("Something Went Wrong, Please check again");
}
});
});
Here is mY controller and I m returning a plan text value.and try to restore this in a php variable
public function avatax(Request $request){
$input = $request->all();
$address=$input['address'];
$pincode=$input['pincode'];
$country=$input['country'];
$state=$input['state'];
$city=$input['city'];
$price=$input['price'];
// print_r(json_decode(json_encode($input)));
// die();
//return response()->json(['success'=>$input]);
$client = new Avalara\AvaTaxClient('phpTestApp', '1.0', 'localhost', 'sandbox');
$client->withSecurity('ABC', 'ABC');
// If I am debugging, I can call 'Ping' to see if I am connected to the server
$p = $client->ping();
echo('<h2>Ping</h2>');
echo('<pre>' . json_encode($p, JSON_PRETTY_PRINT) . '</pre>');
if ($p->authenticated == true) {
echo '<p>Authenticated!</p>';
}
// Create a simple transaction for $100 using the fluent transaction builder
$tb = new Avalara\TransactionBuilder($client, "ABC", Avalara\DocumentType::C_SALESINVOICE, 'ABC');
$t = $tb->withAddress('SingleLocation',$address,null,null, $city,$state,$pincode, $country)
->withLine($price, 1, null, "P0000000")
->create();
// echo('<h2>Transaction #1</h2>');
// echo('<pre>' . json_encode($t, JSON_PRETTY_PRINT) . '</pre>');
// echo '<pre>';print_r($t);
$ta=$t->totalTax;
// die();
return response($ta)
->header('Content-Type', 'text/plain');