How to solve Notice: Undefined index: id in C:\xampp\htdocs\invmgt\manufactured_goods\change.php on line 21 [duplicate]

Answer 1

if you are getting id from url try

$id = (isset($_GET['id']) ? $_GET['id'] : '');

if getting from form you need to use POST method cause your form has method="post"

 $id = (isset($_POST['id']) ? $_POST['id'] : '');

For php notices use isset() or empty() to check values exist or not or initialize variable first with blank or a value

$id= '';