Rough answer to get you started.
Inside the loop, use the row’s record number (a field called ‘IDnumber’, unique, auto) to help name the of a .
The hidden <input> should have an id of something like
<input hidden name="idnumber" value="<?php echo $row[idnumber];?>">
which will cause the vaue of that input field to be the record number of that record. (The <input> statements should be outside of PHP blocks.)
Use the $_POST values to determine which record to update by using the value of the hidden input item (‘idnumber’) – which will be the record number you want to update with the other values in the form.
The loop should be surrounded by a <form> block (outside the loop).