return json() data and fetch it in php

You can simply use the json_encode() function to return JSON response from a PHP script. Also, if you’re passing JSON data to a JavaScript program, make sure set the Content-Type header.

Let’s take a look at an example to understand how it basically works:

$project_id = $row["id"];
$slug = $row["slug"];

$data = ['project_id' => $project_id, 'slug' => $slug];
echo json_encode( $data );

$.ajax({
url:'https://forlancer.in/php/app/update_project_status.php',
method:'POST',
data:{freelancer_id: freelancer_id},

success:function(data){
let Data = JSON.parse(data); // string to object convertion
console.log(Data.project_id); 
// window.location.href="https://forlancer.in/manage-project";
}


});