How to solve this php error?

Question

Notice: Undefined variable: mysqli in C:\xampp\htdocs\TSK\amount.php on line 30

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\TSK\amount.php on line 30
Failed

Line 30:
$result=mysqli_query($mysqli,"INSERT into amount values('$SENDER_Name','$RECIVER_Name','$Amount')");

Answer 1

You should define mysqli variable at first and then use that.
Use mysqli_connect function for mysqli declaration.