A transparent QR code is just a code whose background layer is removed, so the dots take on whatever you place them on. The PNG export keeps the alpha channel; the SVG has no background rectangle at all. Both are sized in the export panel.
What you place it on decides whether it scans. Light, plain or softly textured backgrounds are fine. Photos, dark colours and busy patterns are not: the decoder needs the light modules to be light. If the background is dark, invert the design instead (light dots) and read the warning in the scan check about Android cameras, or keep a soft plate behind the code.
Transparent codes are the right choice for designers placing a code into a layout in Figma, Canva, InDesign or Illustrator. Export SVG and the dots stay vectors you can recolour there.
Questions
Does a transparent QR code scan?
On a light, quiet background yes. On a photo or dark colour, usually not. The quiet zone (margin) still needs to be clear space.
Is the SVG editable?
Yes. Dots are paths, eyes are separate paths, so you can recolour parts in any vector editor.