If Background Remover is unavailable
Keep the original photo, then use an image-editing method outside Canva that explicitly lets you save the result you need. Remove the photo background there and inspect the saved file before bringing it into your design. In Canva, upload that file, place it on the page, and set a contrasting page color temporarily. If you see only the subject, you can position, resize, and layer it like another image. If you see a rectangle, revisit the saved file: renaming a photo with a PNG extension does not create transparency. Availability, export formats, and usage limits vary between editing services, so confirm them in the tool you choose rather than assuming every remover supplies a transparent file.
KEY DISTINCTION
The removal happens before the image enters Canva; Canva is where you compose the design.