<?include "conninfo.php";
$id=$_POST["id"];

$query="SELECT * FROM people WHERE id=$id";
$result=mysqli_query($link,$query);
$r=mysqli_fetch_array($result);//one record only, so no loop


?>

<form action="commitedit.php" method="post">
First name:<input type="text" name="fname" 
value="<?echo $r["firstname"];?>"><br>

Surname: <input type="text" name="sname"
value="<?echo $r["surname"];?>"
>

<input type="hidden" name="id" value="<?echo $id;?>">
<br><br>
<input type="submit" value="Commit Edit">
</form>