diff --git a/invoices.php b/invoices.php
index 5aafab69..de38e53e 100644
--- a/invoices.php
+++ b/invoices.php
@@ -209,14 +209,46 @@ $num_rows = mysqli_fetch_row(mysqli_query($mysqli, "SELECT FOUND_ROWS()"));
                 <table class="table table-striped table-borderless table-hover">
                     <thead class="text-dark <?php if ($num_rows[0] == 0) { echo "d-none"; } ?>">
                         <tr>
-                            <th><a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_number&order=<?php echo $disp; ?>">Number</a></th>
-                            <th><a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_scope&order=<?php echo $disp; ?>">Scope</a></th>
-                            <th><a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=client_name&order=<?php echo $disp; ?>">Client</a></th>
-                            <th class="text-right"><a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_amount&order=<?php echo $disp; ?>">Amount</a></th>
-                            <th><a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_date&order=<?php echo $disp; ?>">Date</a></th>
-                            <th><a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_due&order=<?php echo $disp; ?>">Due</a></th>
-                            <th><a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=category_name&order=<?php echo $disp; ?>">Category</a></th>
-                            <th><a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_status&order=<?php echo $disp; ?>">Status</a></th>
+                            <th>
+                                <a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_number&order=<?php echo $disp ?>">
+                                    Number <?php if ($sort == 'invoice_number') { echo $order_icon; } ?>
+                                </a>
+                            </th>
+                            <th>
+                                <a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_scope&order=<?php echo $disp; ?>">
+                                    Scope <?php if ($sort == 'invoice_scope') { echo $order_icon; } ?>
+                                </a>
+                            </th>
+                            <th>
+                                <a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=client_name&order=<?php echo $disp; ?>">
+                                    Client <?php if ($sort == 'client_name') { echo $order_icon; } ?>
+                                </a>
+                            </th>
+                            <th class="text-right">
+                                <a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_amount&order=<?php echo $disp; ?>">
+                                    Amount <?php if ($sort == 'invoice_amount') { echo $order_icon; } ?>
+                                </a>
+                            </th>
+                            <th>
+                                <a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_date&order=<?php echo $disp; ?>">
+                                    Date <?php if ($sort == 'invoice_date') { echo $order_icon; } ?>
+                                </a>
+                            </th>
+                            <th>
+                                <a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_due&order=<?php echo $disp; ?>">
+                                    Due <?php if ($sort == 'invoice_due') { echo $order_icon; } ?>
+                                </a>
+                            </th>
+                            <th>
+                                <a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=category_name&order=<?php echo $disp; ?>">
+                                    Category <?php if ($sort == 'category_name') { echo $order_icon; } ?>
+                                </a>
+                            </th>
+                            <th>
+                                <a class="text-dark" href="?<?php echo $url_query_strings_sort; ?>&sort=invoice_status&order=<?php echo $disp; ?>">
+                                    Status <?php if ($sort == 'invoice_status') { echo $order_icon; } ?>
+                                </a>
+                            </th>
                             <th class="text-center">Action</th>
                         </tr>
                     </thead>