A PNG stores pixels; an SVG stores shapes. Converting PNG to SVG is not a format change but tracing: the tool groups the image into a small number of colours, finds the outline of each colour area and writes those outlines as SVG paths that can be scaled to any size.
This tool traces with the open-source ImageTracer library, running in your browser. Choose a style (Logo / icon for flat colours and sharp corners, Illustration for smoother curves, Detailed to keep small shapes), set how many colours to keep, and watch a side-by-side preview update as you change them. The download is traced at full detail.
Honest limits: tracing works well on logos, icons, line art, signatures and flat illustrations with clear edges. Photos, gradients, shadows and soft textures don't vectorise well: they turn into flat patches of colour (a poster effect) and very large files, and the tool warns you when an image looks like a photo. A small or blurry PNG also traces with wobbly edges, so use the largest, cleanest version of the logo you have.