Update invoice.md

Author: laujan

articles/ai-services/document-intelligence/prebuilt/invoice.md

@@ -187,7 +187,7 @@ For a complete list of supported languages, *see* our [prebuilt model language s
 
 :::moniker range=">=doc-intel-3.1.0"
 
-* For supported document extraction fields, refer to the **invoice model schema** page in our GitHub sample repository.
+* For supported document extraction fields, *see* the [**invoice model schema**](https://github.com/Azure-Samples/document-intelligence-code-samples/blob/main/schema/2024-11-30-ga/invoice.md) page in our GitHub sample repository.
 
 * The invoice key-value pairs and line items extracted are in the `documentResults` section of the JSON output.