Which document would likely not include a specific layout or style guidelines?

A personal letter typically reflects the individual's style and personal expression, which allows for greater flexibility in formatting and layout compared to more formal documents. While reports, invoices, and agendas often adhere to established formats to ensure consistency and professionalism, a personal letter is less likely to follow strict guidelines, enabling the writer to personalize its appearance. This flexibility can include variations in font, margins, spacing, and overall structure, as the primary focus is on conveying a message in a manner that feels authentic to the writer.