WooCommerce Checkout Add-Ons is a popular extension for the WooCommerce e-commerce platform.

It allows online store owners to add custom fields, options and upsells to the checkout page of their online store.

With Checkout Add-Ons, store owners can create custom field types, including text fields, text areas, drop-downs, multi-selects, radio buttons, checkboxes, multi-checkbox lists, and file uploads.

These custom fields can be used to gather information from customers, such as gift messages, special delivery instructions, or personalized product options.

Additionally, store owners can add options for add-on services and upsell, such as shipping insurance or rush handling.

These options can be set up with fixed-amount or percentage-based costs, depending on how customers interact with the field.

This extension also allows store owners to create conditional add-ons that appear or change based on factors like cart subtotal, products in the cart, or the value of another add-on.

This allows for more personalized and relevant upsell opportunities for customers.

Another key feature of Checkout Add-Ons is the ability to dynamically update order details and the total at checkout as options are selected or modified.

This provides customers with a real-time view of their order total, including any add-on costs.

Checkout Add-Ons extension is also compatible with the WooCommerce Subscriptions extension, allowing store owners to add add-ons to the initial purchase and, optionally, to renewal orders.

This is especially useful for subscription-based e-commerce stores that want to offer customers additional services or options with each recurring payment.

Other features of Checkout Add-Ons include compatibility with the One Page Checkout extension, which gives the ability for customers to view selected add-ons from order detail pages and emails, and the ability for store owners to sort and filter the WooCommerce Orders page based on add-ons and their values.

Finally, the Checkout Add-Ons extension saves selected options and uploads, even if customers browse away from checkout.

This ensures that customers can easily return to their checkout progress without losing any information or selections.

Overall, WooCommerce Checkout Add-Ons is a powerful extension that offers a variety of customization options for online store owners, helping to improve the checkout experience for customers and increase revenue through personalized upsell opportunities.