> ## Documentation Index
> Fetch the complete documentation index at: https://www.twicecommerce.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# How to add an add-on to an order

> Put an add-on a customer forgot on an order they already have, attach it to the line it goes with, and send a checkout link for its price.

> [card] [Open in TWICE Admin](https://admin.twicecommerce.com/orders)
>
> orders

Add an add-on when a customer who already booked asks for an accessory that goes with one of their items, such as a helmet for a bike. It joins the order attached to that item's line, and you send the customer a checkout link for its price. [Line Items](https://www.twicecommerce.com/docs/orders/order-tabs/line-items.md) explains how add-on lines attach and are priced.

To add a listing the customer can book on its own, follow [Add an item](https://www.twicecommerce.com/docs/guides/orders/add-an-item.md) instead.

## Prerequisites

> [!WARNING]
>
> **Required permissions:** **Create and edit orders** to add the add-on (`orders:order_summary:manage`) and to send the checkout link (`orders:order:create`), and **View orders** to follow the payment on the **Payments** tab (`orders:order_payments:view`). Every built-in role holds both, Member included. See [Users & Roles](https://www.twicecommerce.com/docs/settings/users-roles.md).

> [!NOTE]
>
> **Have ready before you start:**
>
> * **The add-on and the line it goes with**, for example the helmet and the customer's bike.
> * **An order that is not closed.** A closed order shows no **+ Add** until you reopen it. See [Reopen an order](https://www.twicecommerce.com/docs/guides/orders/reopen-an-order.md).
> * **The customer's email**, to send the checkout link to.
> * **A payment provider connected**, for the online payment methods the link offers. See [Payments settings](https://www.twicecommerce.com/docs/settings/payments.md).

## The walkthrough

**1. Open the order**

Open **Orders** and find the order. Check the location selector in the top-left corner first if your account has more than one location, because the table lists only that location's orders. The order opens on its **Summary** tab.

![The Orders table with an order's row highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-01.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=cf53ebb5a90d71004e545c40f048e204)

**2. Open the Add-ons tab**

Click **+ Add** in the top-right corner of the order, then the **Add-ons** tab at the top of the **Add** panel that opens. The tab lists the add-ons recommended for this order: the ones attached to its listings, and the ones offered at checkout.

![The Add panel on its Add-ons tab, with the tab highlighted and the recommended add-ons listed](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-02.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=1caee00d14f2a0da1e73acb2bdb275e1)

**3. Pick the add-on**

Enter the add-on's name in **Search anything** at the top. If it is not listed, choose **All** under **Add-ons** on the left. Each row shows the add-on's price, such as From 10.00 € or 10% of parent price. Click the add-on's row.

![The Add-ons tab searched for an add-on, with Search anything, All and the add-on's row highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-03.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=006d6efbfe0dfd52be38f1c1585ee77c)

**4. Choose the line it goes with**

Under **"Select which item this is an add-on to:"**, click the line the add-on goes with. Lines are listed under their customer's name, each with its dates. Pass over **Whole order** and the customer rows above them. The **Add Line Item** panel opens with the add-on.

![Select parent item with the question and the booking line it goes with highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-04.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=9af159be8fddb65eed44dbf502b8c6fb)

**5. Check the dates and the price**

Check **Start** and **End**, copied from the line you chose; a sale add-on shows **Sales date**. **Unit price** starts at the add-on's price for that line. Enter another to change it. Choose the add-on's option, such as a size, if it has one: until then the card reads **Please select all options** and **Add** is greyed out.

![The Add Line Item panel for the add-on with Start, End, Unit price and the option field highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-05.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=7ce6fbb64ab3a66082873f0ac07a48b9)

**6. Add the add-on**

Click **Add** at the bottom of the panel. The panel closes, and the **Summary** tab lists the add-on, with **Add-on to** and its line's name above its own name. Its chip reads **Unpaid**, and the **Payments** card on the right of the order reads **Partially paid**.

![An order's Summary tab with the add-on's Add-on to caption, its Unpaid chip and the Payments card at Partially paid highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-06.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=ad0a7a7f2c58f82cc057247b89e1c6d3)

**7. Open Send checkout link**

Click **Payment** in the top-right corner of the order and choose **Send checkout link**. The **Send checkout link** panel opens on the right.

![The Payment menu open on an order with Send checkout link highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-07.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=e1944f348641dac180d227b4faa1f3d7)

**8. Check the email and what the link collects**

Check **Email** under **Contact details**. It starts with the email of the order's main customer. Check the rows under **Amount to collect**: every line that still owes money is ticked at what it owes. On an order that was paid in full, that is the add-on alone. Untick any other row.

![The Send checkout link panel with the Email field and the Amount to collect section highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-08.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=c6328b64bd103465a5fa5e5fff3d78f6)

**9. Send the link**

Check that the online methods under **Available payment methods** are ticked, then click **Send checkout link** at the bottom of the panel. The button ends in the amount, for example 10.00 €. **Checkout link created successfully** confirms it, and the panel closes.

![The bottom of the Send checkout link panel with Available payment methods and the Send checkout link button highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-09.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=d66f82564c8d0c9db54b5a668d54966c)

**10. Follow the payment**

Open the order's **Payments** tab. The link is listed under **Checkout links** as **Active**. When the customer pays, it reads **Used**, and the add-on's chip on the **Summary** tab reads **Paid**.

![An order's Payments tab with the tab, the Checkout links card and an Active link highlighted](https://mintcdn.com/twicecommerce/Xb60y2g9KnzGSZm2/images/guide-add-an-add-on-to-an-order-10.webp?fit=max\&auto=format\&n=Xb60y2g9KnzGSZm2\&q=85\&s=e708c89e6cabd4b02d0d85bc7d641126)

## How do I know it worked?

* **The add-on is on the Summary tab** with **Add-on to** and the name of the line you picked.
* **The order total includes it**, at the price you left or entered.
* **The link is listed under Checkout links** on the **Payments** tab, and the add-on's chip reads **Paid** once the customer pays.

## Troubleshooting / common pitfalls

> [accordion] The add-on is not in the list
>
> **Recommended** lists only the add-ons attached to the listings on the order and the ones offered at checkout. Choose **All** to see every add-on offered at the order's location. An add-on missing there too is not set up as an add-on for that location. See [Add-on settings](https://www.twicecommerce.com/docs/catalog/listings/addons.md).

> [accordion] The line you want is not offered
>
> An add-on attached to listings is offered only for the lines of those listings. One offered only at checkout goes on the whole order or a customer, never a line. A line that is itself an add-on is never offered. Check which listings carry the add-on in [Add-on settings](https://www.twicecommerce.com/docs/catalog/listings/addons.md).

> [accordion] There is no + Add, or no Add-ons tab
>
> With no **+ Add**, the order is closed. Reopen it as [Reopen an order](https://www.twicecommerce.com/docs/guides/orders/reopen-an-order.md) shows. With **+ Add** but no **Add-ons** tab, your role hides the tab. See [UI visibility](https://www.twicecommerce.com/docs/concepts/admin/visible-areas.md).

## Related articles

> [card] [Line Items](https://www.twicecommerce.com/docs/orders/order-tabs/line-items.md)
>
> How add-on lines attach to their parent and how they are priced.

> [card] [Changing an order](https://www.twicecommerce.com/docs/guides/orders/edit-an-order)
>
> Every walkthrough for changing an order a customer already has.

> [card] [Add an item](https://www.twicecommerce.com/docs/guides/orders/add-an-item.md)
>
> Put another listing on the order at the dates the customer wants.

> [card] [Send a checkout link](https://www.twicecommerce.com/docs/guides/orders/send-a-checkout-link.md)
>
> Collect what an order owes, in full or in part.

> [card] [Add-on settings](https://www.twicecommerce.com/docs/catalog/listings/addons.md)
>
> Which listings carry an add-on, and how its price is set.


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