# Add Numeral to Campaigns

*Click* on **CRM > Campaigns >** *Click* on the blue **Edit** button located next to the Campaign you want to add Numeral to.

* Numeral can be added to an entire campaign or to individual campaign products.
  * It is recommended to add Numeral to the campaign. Go to **General Details**. Look for Tax Service under **Billing Options**. *Click* the drop down and select a **Numeral** service. Then Click on the blue **Update** button.
  * To add Numeral to individual campaign products, go to **Offers** or **Upsells**. Look for Tax Service under **General Options**. *Click* the drop down and select a **Numeral** service. Then Click on the blue **Update Product** button. A tax service on the product will override the campaign service. Different services on products and campaigns will cause multiple calls to Numeral on a single order, if needed.
* On the campaign go to **General Details** and check the box next to “Auto Tax Calculation” if you want it to automatically calculate the sales tax and then click the blue **Update** button.

{% hint style="info" %}
Auto Tax Calculation will automatically determine the sales tax rates on the checkout page. This works for CheckoutChamp hosted pages and Order Entry.\
\
The Auto Tax Calculation option does not have any affect on Direct API checkout pages. To calculate tax on the checkout page for Direct API checkout pages, call the CheckoutChamp [Order Sales Tax API](https://apidocs.checkoutchamp.com/?version=latest#e2ae6a7b-b460-4695-8320-ae17315ad072) before submitting the checkout page (shipping address must be acquired from the customer).
{% endhint %}

{% hint style="info" %}
If you do not use Auto Tax Calculation and do not call the Order Sales Tax API, then the tax will calculate upon the order submission.
{% endhint %}

{% hint style="success" %}
When passing the data to the CheckoutChamp API, please be sure to use Alpha-2 ISO country codes, as found in our [API documentation](https://apidocs.checkoutchamp.com/?version=latest#44c16a19-da53-44df-9a00-8e8c3d2459be).
{% endhint %}


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