Unstructured documents are those that do not have a predefined format or layout, and therefore cannot be easily processed by traditional methods. They often contain free-form text, images, tables, and other elements that vary from document to document. Examples of unstructured documents include contracts, agreements, emails, letters, reports, articles, and so on. UiPath Document Understanding is a solution that enables the processing of unstructured documents using AI-powered models and RPA workflows1.

The other options are not correct because they are examples of structured or semi-structured documents. Structured documents are those that have a fixed format or layout, and can be easily processed by rules-based methods. They often contain fields, labels, and values that are consistent across documents. Examples of structured documents include banking forms, tax forms, surveys, identity cards, and so on. Semi-structured documents are those that have some elements of structure, but also contain variations or unstructured content. They often require a combination of rules-based and AI-powered methods to process. Examples of semi-structured documents include invoices, receipts, purchase orders, medical bills, and so on2.

References: 1: Unstructured Data Analysis with AI, RPA, and OCR | UiPath 2: Structured, semi structured, unstructured sample documents for UiPath document understanding - Studio - UiPath Community Forum