SIS ID is a generic term for Student Information System identifier. The computer system at your school has some form of internal identifier as part of the database of students, teachers, and classes. As your school uses electronic records of some kind, there exists some form of ID to distinguish between people and classes.
This information can typically be exported directly from your system. If you need help determining exactly what information is needed to roster with Kidblog, please see our detailed data specifications for your preferred log in method (found under the org Rostering page).