pls explain following writing taskes letter of inquiry and factual descripition

A letter of inquiry is one in which you enquire about something that you need to know. For example, you can write a letter to the controller of examination enquiring about the tentative dates for the examination. It is an attempt to gather a piece of information that is important to you. On the other hand, a factual description is a paragraph describing a particular place, thing or topic that helps you read more about the topic and gain a complete idea about the subject. It is for learning purpose.