Add a short description to a survey
No Out of Box way to achieve this
If you are using the assessment_take2 page then there is no Out Of Box way to achieve this currently in our platform but here are some Community Articles that might lead you in the right direction: https://community.servicenow.com/community?id=community_question&sys_id=71904b25db98dbc01dcaf3231f961990&view_source=searchResult
If you plan on using Surveys in the Service Portal, this is currently supported in our Out Of Box instance. This comes from the take_survey widget.