The the Form used by the OOB Report an Issue ( I think it's named Issue Details) offering has a few special (hidden) fields that translate to SDM attributes (you can
If have configured the SDM integration in the Catalog, you might have noticed a setting called Attributes prefix. (by default I think is ca_sdm_attr_. What this does is parses any fields in the Form and if the name of the field is prefixed with ca_sdm_attr_, then it's value is stored in the SDM Request/Incident corresponding attribute.
This means that if you modify the Form and add 2 fields ca_sdm_attr_customer and ca_sdm_attr_requestor, then the values of those form fields will be sent to SDM in order to fil in the Requestor and Affected End User.