When a form is submitted, Notice: Undefinedindex: myfile appears.

Notice: Undefinedindex: myfile appears in the submitted form, as shown in the following figure. when the form is submitted, Notice: Undefined index: myfile in D: \ WWW \ course \ admin \ alluser appears. php on line 10 error,
The content of the form cannot be passed, and a null value is displayed.


Php code:
Include_once ("../login/config. php ");
If (! Empty ($ _ FILES ["myfile"]) {
$ File = $ _ FILES ["myfile"];
}
If ($ _ FILES ["myfile"] ["error"]> 0)
{
Echo "Error:". $ _ FILES ["myfile"] ["error"]."
";
}
Else
{
Echo "Upload:". $ _ FILES ["myfile"] ["name"]."
";
Echo "Type:". $ _ FILES ["myfile"] ["type"]."
";
Echo "Size:". ($ _ FILES ["myfile"] ["size"]/1024). "Kb
";
Echo "Stored in:". $ _ FILES ["myfile"] ["tmp_name"];
}
$ Filename = $ _ FILES ['myfile'] ['name'];
$ Filepath = $ _ FILES ['myfile'] ['tmp _ name'];
// $ Filepath = "";
Echo"