How do I upload photos of my signature from my phone so that the signature looks natural on the doc?

I used to be able to take a photograph of my signature with an iPhone then download it to PDFiller, which would transpose it to the doc in a way that looked natural and not as if I pasted a photo to it. It seems I can no longer do this (so I use old, saved signatures). And the feature that allows you to "draw" your signature comes out looking artificial. Is there a reason why it no longer use photo images and so they match the background on the doc?