Set the token on <head> of your default.blade.php.
<meta name="csrf-token" content="{{csrf_token()}}">
Add ajaxSetup on the top of your script, that will be accessible to everywhere. This will set headers on each ajax call
$.ajaxSetup({
headers: {
'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
}
});