Hi There!
Great question. I'm going to share some guides and some information that I hope might help.
Uploading non-Canvas Badges/Credentials badges to a backpack. This guide has step-by-step instructions for how to take a badge that you've earned elsewhere and add it to your Canvas Badges/Credentials backpack. A key element to keep in mind is that in order for this to work, the badges must be "Open Badges." Here's a document explaining what Open Badges are and a great resource to help determine whether a badge in question is indeed an Open Badge. If it's NOT an Open Badge, then you will, unfortunately, not be able to add it to your Canvas Badges/Credentials backpack.
I hope that this helps!