why finger of hands and feet become wrinkled due to to water?
There are a few hypothesis around it, but it is known that its associated with the function of distal nerves of the hands and feet. I suggest reading this short case for a glimpse at this - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2464382/

Also another tip I can give is that professional swimming athletes for example, eventually experiment an adaptation process in which this wrinkling reaction diminishes due to being exposed to the same stimuli repeatedly and for long periods of time.