When financial transactions are entered, what accounting detail cannot be changed?

The correct choice centers around company currency, which is a fundamental parameter in accounting that is established at the organizational level. Once set, the company currency remains fixed for all financial transactions processed within that specific entity. This is crucial for maintaining accurate financial reporting and compliance with accounting standards, as currency impacts all financial operations and reporting metrics.

When transactions are recorded in a company's financial system, the accounting software typically uses the designated company currency to ensure consistency across all reports and entries. Changing the company currency post-transaction could lead to significant discrepancies in financial data, making it a non-negotiable parameter.

In contrast, other details such as account type, transaction date, and transaction amount are often subject to modification based on organizational policies and accounting practices. For instance, a transaction date may be adjusted to reflect a correction or an update, and transaction amounts can change to correct errors or accommodate additional charges or discounts. Thus, while these aspects of a transaction can be altered, the company currency remains a stable, unchangeable element in the backdrop of financial transactions to preserve the integrity of the accounting system.