Which AWS service will meet these requirements?

Explanations:

Amazon Forecast is used for time-series forecasting and predictive analytics. It is not designed for analyzing or extracting data from documents like invoices.

Amazon Textract is a machine learning service that automatically extracts text and data from scanned documents. It is specifically designed to read and interpret invoices, making it suitable for identifying total balance amounts.

Amazon Rekognition is a service that provides image and video analysis. It can identify objects, scenes, and faces but does not specialize in reading or extracting text from documents like invoices.

Amazon Lex is a service for building conversational interfaces using voice and text. It does not provide capabilities for extracting data from documents, making it unsuitable for the given requirement.