How do you get around the 3MB upload limit?

I’m trying to upload an education certificate from my Muay Thai gym, which came as two PDFs. The system only allows a single PDF, so I combined them—but now the file is 4.9MB, which is over the limit.

I’ve tried compressing it in Canva, but the quality becomes too low to read. I also tried exporting the pages as images and resizing, but I’m still struggling to get it under 3MB.

It’s a 10-page document.