AWS innovate Migrate Modernize Build

I apologize, but I don't have specific information about certificates for the AWS Innovate Migrate Modernize Build event you mentioned. Generally, for AWS events, certificates are handled by the event organizers rather than through AWS services directly.

If you participated in an official AWS event and were promised a certificate, the best course of action would be to contact the event organizers directly. They should be able to provide you with information on how to obtain your certificate or resolve any issues related to receiving it.

For future reference, if you're looking to obtain AWS certifications, those are typically acquired through official AWS Certification exams, not through watching presentations or attending events. However, events can often provide valuable learning experiences that can help prepare you for certification exams.
Sources
Certificate issues | AWS re:Post