There are different types of texts. But, generally they are usually informative and persuasive. Informative texts aim to educate or convey awareness.
Persuasive texts, on the other hand, aim to influence others’ beliefs, opinions, or mindset regarding certain topics or issues. Any informative or persuasive text conveys a message.
A message is the smallest unit of meaning in communication intended by the source (speaker or writer) for consumption by a recipient or a group of recipients (listener or reader) delivered through various means - orally (face-to-face communication, tele/cellular phone), pseudo-orally (chats, texts), or through written communication (letters, books, newspapers).
While messages are generally conveyed through verbal means, they are also emphasized through non-verbal expressions - tone (which is highlighted by the voice in oral communication and choice of words in written communication) and facial and bodily gestures. The message and how it is constructed constitute the informativeness or persuasiveness of a text.
Great article