Azure Form Recognizer, now part of Azure AI Document Intelligence, is the correct service. It is specifically designed to extract text, layout, and key-value pairs from documents. Crucially, it includes a Personally Identifiable Information (PII) detection feature that can be enabled during analysis. This feature identifies sensitive data such as names, addresses, social security numbers, and financial information within the document's content, allowing for its identification or redaction.

A. Custom Vision is an image analysis service used for building custom image classification and object detection models. It does not analyze text content within documents for sensitive information.

B. Conversational Language Understanding (CLU) is designed to build natural language understanding models for conversational applications, such as chatbots, to identify user intents and entities from utterances.

1. Microsoft Learn

Azure AI Document Intelligence Documentation

"PII detection feature": "The PII detection feature can identify and redact sensitive information in the document analysis output... The PII feature is available with the 2023-07-31 (GA) and later API versions and can be enabled on the Read and Layout models by using the features query parameter."

2. Microsoft Learn

AI-900 Study Guide

"Analyze text": This section describes the capabilities of the Azure Cognitive Service for Language

which includes PII detection. However

Form Recognizer (Document Intelligence) is the specialized service for processing forms and documents and integrates this capability directly for document-centric workflows. The question specifically asks about documents.

3. Microsoft Learn

"What is Custom Vision?": "Azure AI Custom Vision is an image recognition service that lets you build

deploy

and improve your own image identifiers." This confirms its purpose is image recognition

not text analysis in documents.