A didactic text is one which is written that contains moral lessons and this can be a text purpose.
This refers to the reason why a writer writes a text which can be to either inform, educate or entertain his readers and can even be a didactic text.
Please note that your question is incomplete so I gave you a general overview to help you get a better understanding of the concept.
Read more about text purpose here:
https://brainly.com/question/24836026