According to the UiPath documentation, the available options for Scoring in Document Manager, that apply only to string content type, are exact match and Levenshtein. Exact match is a scoring strategy that considers a prediction to be correct only if it exactly matches the true value. Levenshtein is a scoring strategy that measures the similarity between two strings by counting the minimum number of edits (insertions, deletions, or substitutions) required to transform one string into another. The lower the Levenshtein distance, the higher the score. These options can be configured in the Advanced tab of the Edit Field window for string fields.
References:
Document Understanding - Create and Configure Fields
Document Understanding - Training High Performing Models

The ML Classifier is a document classifier that uses a machine learning model deployed as an ML Skill in AI Center to perform document classification tasks. The ML Classifier can work by default with Invoices, Purchase Orders, Receipts, and Utility Bills, or with custom document types that are trained using the Data Manager and the Machine Learning Classifier Trainer12.
According to the best practice, the ML Classifier is the only recommended classifier to be used when the custom document types are very similar and file splitting is not necessary. This is because the ML Classifier can handle complex and ambiguous cases where the document types are hard to distinguish by rules or keywords, and can also learn from feedback and improve over time. File splitting is not necessary when the documents are single-page or have a consistent number of pages per document type3.
The other options are not correct because they are scenarios where other classifiers, such as the Keyword Based Classifier or the Intelligent Keyword Classifier, can be used in combination with the ML Classifier or instead of it. These classifiers are based on rules or keywords that can identify the document types based on their content or metadata, and can also perform file splitting if the documents are multi-page or have a variable number of pages per document type3.
References: 1: Machine Learning Classifier - UiPath Activities 2: Machine Learning Classifier Trainer - UiPath Document Understanding 3: Document Classification - UiPath Document Understanding

Reference: UiPath IntelligentOCR Activities - LoadTaxonomyFile

Reference: UiPath Communications Mining

When setting up a classification label in UiPath's Out Of the Box (OOB) labeling templates, you need to provide several key details: the name of the label, the classification type (which defines the kind of label), the input to be labeled, the attribute name that describes the label's context, a shortcut for quick access, and a color for visual distinction. These fields ensure the label is fully defined and easy to manage in workflows.
(Source: UiPath Document Understanding documentation)