# Use a predefined schema

> :::important
To create a document type, we strongly recommend that you follow the "Create Document Type" flow in Document Understanding<sup>TM</sup>. This will automatically populate the correct schema, reducing tedium and costly mistakes. If you want to use AI Center, follow the instructions below.
:::

:::important
To create a document type, we strongly recommend that you follow the "Create Document Type" flow in Document Understanding<sup>TM</sup>. This will automatically populate the correct schema, reducing tedium and costly mistakes. If you want to use AI Center, follow the instructions below.
:::

To use the retraining capability in AI Center, you need to use a set of fields based on the fields already extracted by the out-of-the-box pre-trained ML Packages offered by UiPath®. This list of fields is called a schema.

To create a predefined schema, follow the steps:

1. Check the complete list of field for the desired endpoint.
   :::note
   Add the `/info/model` suffix to the URL of the endpoint you want to use. You can find the list public endpoints URL on the [Public endpoints](https://docs.uipath.com/document-understanding/automation-cloud/latest/classic-user-guide/public-endpoints#public-endpoints-for-automation-cloud-and-test-cloud) page. For example, `https://du.uipath.com/ie/invoices/info/model`. For an enhanced reading experience of the fields list, it's recommended to install a JSON viewer extension in your browser.
   :::
2. Copy the content of the inside the `schema:{}` object.
   :::note
   Only the content between the curly brackets must be copied.
   :::
3. Paste the content in the editor of your choice.
4. Save the file with a name using the following format: `YourFile_schema.json`.