> Shopify Plus: > [Checkout UI extensions](/docs/api/checkout-ui-extensions) that render on the information and shipping and payment steps in checkout are available only to stores on a [Shopify Plus](https://www.shopify.com/plus) plan. This guide introduces custom banners and fields, and describes the available resources that you can use to build them in Shopify checkout. ## How it works You can build functionality in your app that allows merchants to display and configure the following experiences: - [Custom banners](#custom-banners) in checkout - [Custom fields](#custom-fields) in checkout ### Custom banners A custom banner is a notice that you can display to customers. For example, you might want to show a banner that indicates that items are final sale and can't be returned or exchanged. You can use a [checkout UI extension](/docs/api/checkout-ui-extensions) to build a custom banner. You can support [static targets](/docs/api/checkout-ui-extensions/latest/extension-targets-overview#static-extension-targets) so that extensions can be rendered using the checkout editor in one of the [supported locations](/docs/api/checkout-ui-extensions/latest/extension-targets-overview) in checkout. The following example shows how to display a banner that renders at the [`purchase.checkout.block.render`](/docs/api/checkout-ui-extensions/latest/apis/extensiontargets) target. ![The custom banner in checkout, indicating that items are final sale and can't be returned or exchanged](/assets/apps/checkout/custom-banner.png) ### Custom fields A custom field is a property that allows users to enter text into a user interface. For example, you might want to create a custom field that collects delivery instructions from customers. You can use a [checkout UI extension](/docs/api/checkout-ui-extensions) to build a custom field. The following example shows a custom field that collects delivery instructions and renders at the [`purchase.checkout.shipping-option-list.render-after`](/docs/api/checkout-ui-extensions/latest/apis/extensiontargets) target: ## Getting started Follow tutorials to learn how to build custom banners and fields.

Build a custom banner

Learn how to add a custom banner to checkout.

Build a custom checkout field

Learn how to add custom fields to checkout that customers can use to add delivery instructions to their order.

## Developer tools and resources Explore the following developer tools and resources to get familiar with building custom banners and fields.

Checkout UI extensions API reference

Consult the API reference for checkout UI targets and their respective types.

Components for checkout UI extensions

Learn about the components that are available in checkout UI extensions.

Checkout extension configuration

Learn about the properties that you can configure in your checkout UI extension.

UX guidelines for custom fields

Explore UX guidelines that you can refer to when building custom fields.