how can i get value from another CRUD in my json - json

Question

i have json return values from order crud how can i make it return also value from User Crud by user ID
this is my code now
public function vendorindex(Request $request)
{
$user = Auth::user();
if(isset($user->id)){
$order = Order::where('vendor_id', $user->id)->get();
}else{
$order = null;
}
return response()->json($order);
}
i tried to do this but not work with me to replace another value with the value that i want
public function vendorindex(Request $request)
{
$user = Auth::user();
if(isset($user->id)){
$order = Order::where('vendor_id', $user->id)->get();
foreach($order as $orders){
$mobile = User::where($user->mobile);
$created_at = Order::where($orders->created_at);
$phonenumber = array(
'mobile' => $mobile,
'created_at' => $created_at
);
$orders->created_at = $phonenumber;
}
}else{
$order = null;
}
return response()->json($order);
}