# Register Endpoint for Custom Content Block Component

Once you know the hosted endpoint for your custom content block UI, you must register that endpoint in an installed package.

:::note
To add content blocks to an existing app, add them as components in the same package.
:::

1. [Create an installed package](/docs/marketing/marketing-cloud/guide/install-packages.md) or navigate to an existing package.
2. Under Components, click **Add Component**.
3. Select **Custom Content Block**.
4. Type a **Name** and **Description** for the content block. This name doesn't display in Content Builder.
5. Enter the **Endpoint URL**, which is the base URL for your block widget. Content Builder loads all assets relative to this endpoint.
6. To complete registration, save the component.

## Related Items

- [List Your App in AppExchange](/docs/marketing/marketing-cloud/guide/list-app-appexchange.md)