Final answer:
Files are chosen based on claim documentation provided such as invoices, receipts, medical records, insurance policies, and other relevant documents.
Step-by-step explanation:
Files chosen by managers or technical support staff for internal claim audits are selected on the basis of the claim documentation provided. This could include invoices, receipts, medical records, insurance policies, and other relevant documents. Managers and technical support staff review these files to ensure claims are valid and meet the requirements set by the company.