You can modify your email address, as well as your whole profile, from the "Edit Profile" screen. You can access this screen on the app by going to your profile and selecting the icon in the top right-hand corner, followed by selecting "Edit Profile" from the menu. To get here on the desktop version, press the down arrow in the top right-hand corner and select "Edit Profile" from the drop-down menu. For your privacy, your email address is only visible to you and is never shared with other users.