In general, student accounts are much more limited and have limited functionality. When you sign up for an account on https://portal.ssat.org, you are in fact creating multiple accounts. You are creating one for you, the parent / guardian. You are simultaneously creating one for each student you entered.
Your parent / guardian account has full power to complete all possible changes, submit orders, add SSAT recipients, etc.
Student accounts are limited to viewing most information, including scores and results. They can also enter very limited information such as a student essay as part of the SAO (Standard Application Online) or start the Snapshot or SSAT at Home, but only if you have already purchased and approved these.
While the student account must be used to complete Snapshot, if you prefer to prevent access to your student's account, you can disable it by doing the following: