how to change the way the url looks but keep the function - php

Question

How do I change my URL's function for calling up on pages?
Here's an example: https://exaplesitename.com/index.php?id=21
What it looks like now but I want it to be something like this: https://exaplesitename.com/Entertainment
This is the navigation code:
<?php
function find_parent_categories($options=[]) {
global $db;
$Active = $options['Active'] ?? 'false';
$sql = "SELECT * FROM Parent_Categories ";
if($Active){
$sql .= "WHERE Active = true ";
}
$sql .= "ORDER BY Category_Order ASC";
$result = mysqli_query($db, $sql);
confirm_result_set($result);
return $result;
}
function find_categories($id_Category_Parent, $options=[]){
global $db;
$Active = $options['Active'] ?? 'false';
$sql = "SELECT * FROM Categories ";
$sql .= "WHERE id_Category_Parent='" . db_escape($db, $id_Category_Parent) . "' ";
if($Active){
$sql .= "AND Active = true ";
}
$sql .= "ORDER BY Category_Order ASC";
$result = mysqli_query($db, $sql);
confirm_result_set($result);
return $result;
} ?>
<nav class="navbar fixed-top navbar-expand-lg bg-white navbar-custom">
<a class="navbar-brand" href="<?php echo url_for('/index.php'); ?>">
<img src="../../images/Logo1.png" alt="Nantucket" class="img-fixed"/>
</a>
<button class="navbar-toggler custom-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent1" aria-controls="navbarSupportedContent1" aria-expanded="false" aria-label="Toggle navigation">Menu
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent1">
<?php $nav_categories = find_parent_categories(['Active' => true]); ?>
<ul class="navbar-nav mr-auto">
<?php while($nav_category = mysqli_fetch_assoc($nav_categories)) { ?>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="<?php echo url_for('index.php?id=' . h(u($nav_category['id']))); ?>" id="navbarDropdown1" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"><?php echo h($nav_category['Category_Name']); ?></a>
<?php $nav_sub_categories = find_categories($nav_category[id], ['Active' => true]); ?>
<ul class="dropdown-menu" aria-labelledby="navbarDropdown1">
<?php while($nav_sub_category = mysqli_fetch_assoc($nav_sub_categories)) { ?>
<li>
<a class="dropdown-item" href="<?php echo url_for('index.php?id=' . h(u($nav_sub_category['id']))); ?>"> <?php echo h($nav_sub_category['Category_Name']); ?></a>
</li>
<?php } //while $nav_sub_categories ?>
</ul>
<?php mysqli_free_result($nav_sub_categories); ?>
<?php mysqli_free_result($nav_categories); ?>
</li>
<?php } ?>
</ul>
</div>
</nav>
Thank you very much for any help and kindness.

Answer 1

Any change in url can be achieved by changing .htaccess file.
RewriteEngine On
RewriteRule https://exaplesitename.com/Entertainment https://exaplesitename.com/index.php?id=21
For more information about .htaccess please refer to:
https://www.smashingmagazine.com/2011/11/introduction-to-url-rewriting/