two ways to send personalized certificates via Google Forms and Google Sheets. What I didn't include in those tutorials was how to create a custom certificate without using the default certificate template found in Google Slides. In the following video I demonstrate how you can design your own customized certificates in Google Slides.
In the video I used Pixabay to find borders to use in my certificate. That's not the only source that you can use. Any site that offers public domain imagery could be used in the same way to design your own certificates.