I assume that you are using webmail for Gmail and not Windows Live. You can access Gmail through Windows Live. As far as I am aware you cannot change the e-mail symbol to open webmail as it hasn't a clue which address to go to.
The Evil Within 2 review-in-progress
InVision Studio takes on Adobe XD and Sketch
Camera tips to take better iPhone photos
Comment transformer un iPhone en borne Wi-Fi ?