I've seen people say it cannot be done in Canva.

You just gotta get a little creative. 

But it has. Darling. 

Apply a Drop Shadow to an Image in Canva

Duplicate
Adjustments
Transparency
Offset
Send to Back

Find an image in Canva, preferably a PNG

Duplicate the Image

Adjust the Image

Adjust the Transparency

Send to Back

Done!

Make it more colorful by applying an Effect

Then Reapply the Blur

No blur kind of has a reflective vibe.

But applying the blur gives it a soft light vibe

If you want to learn how to apply a shadow like this, read the full article.