Allow customer to change the order status in WooCommerce My account

I know I might be a bit late. But here I am answering this question in case anyone still needs it.

The below code will add a Mark As Completed button in the My Account Order page action list. Please be informed that it checks if the order status is set to Delivered by the admin and then it shows the button to the customers.

I have developed a plugin for this as well and it's available on WordPress repository. You may check it out in case you need it. Order Approval by Customer for WooCommerce.

/*================================
    Add Delivered Order Status
==================================*/

add_action( 'init', 'msoa_register_delivered_order_status' );
function msoa_register_delivered_order_status() {
    register_post_status( 'wc-delivered', array(
        'label'                     => 'Session Completed',
        'public'                    => true,
        'show_in_admin_status_list' => true,
        'show_in_admin_all_list'    => true,
        'exclude_from_search'       => false,
        'label_count'               => _n_noop( 'Delivered <span class="count">(%s)</span>', 'Delivered <span class="count">(%s)</span>' )
    ) );
}

add_filter( 'wc_order_statuses', 'msoa_add_delivered_status_to_order_statuses' );
function msoa_add_delivered_status_to_order_statuses( $order_statuses ) {

    $new_order_statuses = array();

    foreach ( $order_statuses as $key => $status ) {

        $new_order_statuses[ $key ] = $status;

        if ( 'wc-processing' === $key ) {
            $new_order_statuses['wc-delivered'] = __( 'Delivered', 'order-approval' );
        }
    }

    return $new_order_statuses;
}

add_filter( 'woocommerce_my_account_my_orders_actions', 'msoa_mark_as_received', 10, 2 );
function msoa_mark_as_received( $actions, $order ) {
    $order_id = $order->id;

    if ( ! is_object( $order ) ) {
        $order_id = absint( $order );
        $order    = wc_get_order( $order_id );
    }
    
    // check if order status delivered and form not submitted

    if ( ( $order->has_status( 'delivered' ) ) && ( !isset( $_POST['mark_as_received'] ) ) ) {
        $check_received = ( $order->has_status( 'delivered' ) ) ? "true" : "false";
        ?>
        <div class="ms-mark-as-received">
            <form method="post">
                <input type="hidden" name="mark_as_received" value="<?php echo esc_attr( $check_received ); ?>">
                <input type="hidden" name="order_id" value="<?php echo esc_attr($order_id);?>">
                <?php wp_nonce_field( 'so_38792085_nonce_action', '_so_38792085_nonce_field' ); ?> 
                <input class="int-button-small" type="submit" value="<?php echo esc_attr_e( 'Mark as Received', 'order-approval' ); ?>" data-toggle="tooltip" title="<?php echo esc_attr_e( 'Click to mark the order as complete if you have received the product', 'order-approval' ); ?>">
            </form>
        </div>
        <?php
    }

    /*
    //refresh page if form submitted

    * fix status not updating
    */
    if( isset( $_POST['mark_as_received'] ) ) { 
        echo "<meta http-equiv='refresh' content='0'>";
    }

    // not a "mark as received" form submission
    if ( ! isset( $_POST['mark_as_received'] ) ){
        return $actions;
    }

    // basic security check
    if ( ! isset( $_POST['_so_38792085_nonce_field'] ) || ! wp_verify_nonce( $_POST['_so_38792085_nonce_field'], 'so_38792085_nonce_action' ) ) {   
        return $actions;
    } 

    // make sure order id is submitted
    if ( ! isset( $_POST['order_id'] ) ){
        $order_id = intval( $_POST['order_id'] );
        $order = wc_get_order( $order_id );
        $order->update_status( "completed" );
        return $actions;
    }  
    if ( isset( $_POST['mark_as_received'] ) == true ) {
        $order_id = intval( $_POST['order_id'] );
        $order = wc_get_order( $order_id );
        $order->update_status( "completed" );
    }

    $actions = array(
        'pay'    => array(
            'url'  => $order->get_checkout_payment_url(),
            'name' => __( 'Pay', 'woocommerce' ),
        ),
        'view'   => array(
            'url'  => $order->get_view_order_url(),
            'name' => __( 'View', 'woocommerce' ),
        ),
        'cancel' => array(
            'url'  => $order->get_cancel_order_url( wc_get_page_permalink( 'myaccount' ) ),
            'name' => __( 'Cancel', 'woocommerce' ),
        ),
    );

    if ( ! $order->needs_payment() ) {
        unset( $actions['pay'] );
    }

    if ( ! in_array( $order->get_status(), apply_filters( 'woocommerce_valid_order_statuses_for_cancel', array( 'pending', 'failed' ), $order ), true ) ) {
        unset( $actions['cancel'] );
    }

    return $actions;

}

New improved answer: Allow customer to change order status in WooCommerce

You can use the following code that will:

• Replace the button text "view" by "approve" on My account > Orders
• Display a custom button to approve the order on My account > Order view (single order)
• Display a custom success message once customer has approved an order

This will only happen on customer orders with a specific status. So you will have to define:

• The order status that require an approval from customer.
• The order status that reflect an approved order by the customer (on the 3 functions)
• The button text for order approval
• The text that will be displayed once customer has approved the order

The code:

// My account > Orders (list): Rename "view" action button text when order needs to be approved
add_filter( 'woocommerce_my_account_my_orders_actions', 'change_my_account_my_orders_view_text_button', 10, 2 );
function change_my_account_my_orders_view_text_button( $actions, $order ) {
    $required_order_status = 'processing'; // Order status that requires to be approved
    
    if( $order->has_status($required_order_status) ) {
        $actions['view']['name'] = __("Approve", "woocommerce"); // Change button text
    }
    return $actions;
}

// My account > View Order: Add an approval button on the order
add_action( 'woocommerce_order_details_after_order_table', 'approve_order_button_process' );
function approve_order_button_process( $order ){
    // Avoiding displaying buttons on email notification
    if( ! ( is_wc_endpoint_url( 'view-order' ) || is_wc_endpoint_url( 'order-received' ) ) ) return;

    $approved_button_text  = __("Approve this order", "woocommerce");
    $required_order_status = 'processing'; // Order status that requires to be approved
    $approved_order_status = 'completed'; // Approved order status

    // On submit change order status
    if( isset($_POST["approve_order"]) && $_POST["approve_order"] == $approved_button_text
    && $order->has_status( $required_order_status ) ) {
        $order->update_status( $approved_order_status ); // Change order status
    }

    // Display a form with a button for order approval
    if( $order->has_status($required_order_status) ) {
        echo '<form class="cart" method="post" enctype="multipart/form-data" style="margin-top:12px;">
        <input type="submit" class="button" name="approve_order" value="Approve this order" />
        </form>';
    }
}

// My account > View Order: Add a custom notice when order is approved
add_action( 'woocommerce_order_details_before_order_table', 'approved_order_message' );
function approved_order_message( $order ){
    // Avoiding displaying buttons on email notification
    if( ! ( is_wc_endpoint_url( 'view-order' ) || is_wc_endpoint_url( 'order-received' ) ) ) return;

    $approved_order_status = 'completed'; // Approved order status

    if( $order->has_status( $approved_order_status ) ) {
        wc_print_notice(  __("This order is approved", "woocommerce"), 'success' ); // Message
    }
}

Code goes in functions.php file of your active child theme (or active theme). Tested and works.

---

On My account > Orders (list):

On My account > Order view (when an order required to be approved):

On My account > Order view (when customer has approved the order):

---

For order statuses, you can create custom order statuses with code or with plugins.