What is the difference between narrative and informational text?

A narrative is a story told from one person's perspective. An informational text is perspective-neutral.

For example, a narrative would be "He saw the forklift driven by a good friend of his brother-in-law." The same event in an informational text format would be "The forklift was driven by a good friend of Bob's brother-in-law." The difference is who is relating the information - in the first example, "he" is the channel for the information while in the second example, there is no specific individual providing the information.