We recommend reaching out to the student's school/district to get the snapcode. Snapcodes are issued by the district and the school should have the information. You can review this article: No-Snapcode.
The student's report card/grade card should be accessible through the dashboard of the PowerSchool Mobile app. The article "What is the PowerSchool Mobile App and how do I download it?" should walk you through the process of how to set up a parent account on the PowerSchool Mobile app to view grades.
Also, we have another thread with a similar question from a user where the process has been discussed in detail. Please click on the link below to see the thread.