> For the complete documentation index, see [llms.txt](https://docs.2checkout.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.2checkout.com/orders/orders/order-tracking/track-sales-with-custom-parameters.md).
# Track sales with custom parameters
## Overview
Define multiple URL parameters to track your sales through the 2Checkout system. The custom URL parameters can be used for tracking at both product and order level.
## Availability
All 2Checkout accounts.
## Create custom parameters
Follow the steps below to create custom parameters to add to products and buy links.
1. Log into your 2Checkout [Merchant Control Panel](https://secure.2checkout.com/cpanel) account.
2. Go to *Setup >* [*Ordering options*](https://secure.2checkout.com/cpanel/order_settings.php)*.*
3. Scroll down to Additional order fields and click on [**Click here to create and manage**](https://secure.2checkout.com/cpanel/additional_fields.php) **additional fields and collect extra information from shoppers at checkout or track orders**.
4. Use the **Add new field** section to define each new field.
* Enter the **Field identifier**. This reference is used to create the URL parameter that you can use in buy links. Use unique identifiers for all your fields. **Note**: This field accepts only alpha-numeric characters. If you leave this field empty, 2Checkout generates a random value as an identifier.
* Enter the **Field text** (the name of the field).
* Set the **Field type** to **Hidden**. Otherwise, otherwise the field will be a Textbox, Checkbox, or Listbox, all of which are visible in the shopping cart. **Hidden** fields help you create custom URL tracking parameters and they are invisible to shoppers.
* Use the **Apply to** drop-down to choose whether the field should apply at the product or order level.
* Use the **Validation rule** field to specify the regular expression to validate the field values.
* Click **Create field** to save the new field.
## Assign custom parameters to products
Follow the steps in the **Create custom parameters** section to create a new **Hidden** parameter and apply it at the **Product** level.
Next, follow the steps below to assign the parameter to a product.
1. Once logged in to your [Merchant Control Panel](https://secure.2checkout.com/cpanel), go to **Setup** and click on [Products](https://secure.2checkout.com/cpanel/products.php).
2. Click **Edit** on the product you want to assign the parameter to.
3. Go to the **Information** tab and scroll to the bottom of the screen. You'll find the previously defined parameter in the **Order additional fields** section. All new parameters are disabled by default.
4. Check the **Enabled** option on the **Order page** column corresponding to the parameter you want to use. Click **Save**.
## Assign custom parameters to orders
Follow the steps in the **Create custom parameters** section to create a new **Hidden** parameter and apply it at the **Order** level.
Next, follow the steps below to assign the parameter to an order.
1. Log into your 2Checkout [Merchant Control Panel](https://secure.2checkout.com/cpanel) account.
2. Go to *Setup →* [*Ordering options*](https://secure.2checkout.com/cpanel/order_settings.php)*.*
3. Scroll down to **Additional order fields**.
4. Check the checkbox next to the parameter you want to use.
5. Click **Save settings** at the bottom of the page.
## Build buy-links using custom parameters
### Build buy-links with per-product parameters
Let's assume you created **customparameter** for Product A with the ID 1234567, and the 2Checkout system created the **ADDITIONAL\_customparameter\[1234567]** URL parameter.
To track sales of this product using **customparameter**, add **ADDITIONAL\_customparameter\[1234567]** to the buy link as such:
```
https://secure.2checkout.com/order/checkout.php?PRODS=1234567&ADDITIONAL_customparameter[1234567]=CustomTrackingSource1
```
You can assign the desired values to custom URL parameters to best serve you in the sales tracking process.
### Build buy-links with per-order parameters
Let's assume you created **customparameter** for orders, and the 2Checkout system created the **ADDITIONAL\_customparameter** URL parameter.
To track orders using **customparameter**, add **ADDITIONAL\_customparameter** to the buy link as such:
```
https://secure.2checkout.com/order/checkout.php?PRODS=1234567&ADDITIONAL_customparameter=CustomTrackingSourceForOrders
```
You can assign the desired values to custom URL parameters to best serve you in the sales tracking process.
Related documentation
* [Products and subscriptions listing query parameters](https://verifone.cloud/docs/2checkout/Documentation/myAccount/Products-and-subscriptions-listing-query-parameters)
* [Subscriber management and self-service](https://verifone.cloud/docs/2checkout/Documentation/Subscription-Billing/03Subscriber-management-and-self-service)
* [Contracts](https://verifone.cloud/docs/2checkout/Documentation/Subscription-Billing/01Subscription-Billing-Set-up/03Contracts)
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