How do I replace “Log Out” from the Menu with “My Orders”?

by

You can work with is_user_logged_in() function to create a if / else statement in your menu.

Here a quick code.

<?php
if ( is_user_logged_in() ) {

    ?>
    <li class="menu-item"><a href="https://website.com/my-account/orders/"><i class="fa fa-handshake-o"></i>My Orders</a></li>
    <li class="menu-item"><a href="https://website.com/my-account/customer-logout/"><i class="avatar"></i>Log out</a></li>
    <?php 

} 
else {

    ?>
    <li class="menu-item"><a class="porto-link-login" href="https://website.com/my-account/"><i class="fa fa-user"></i>Log In</a></li>
    <?php 
}
?>

You could also work with the current user capabilities current_user_can to create a better filter for your menus.

I will give you the documentation below if you want to go further.

Documentation : https://developer.wordpress.org/reference/functions/is_user_logged_in/
https://codex.wordpress.org/Function_Reference/current_user_can