Asocial norm that reflects how things are typically done is considered whereas a social norm that reflects what behaviors are approved is considered descriptive; prescriptive normative; informational prescriptive; descriptive informational; normative

I believe the answer is: descriptive; prescriptive
Descriptive social norm usually would directly told and accompanied by expectation to be followed.
Prescriptive social norm on the other hand Tend to not be expected, but always considered as a good will if being done (such as sending thank you note after job interview)