"Email" in your phone is a pre-installed app that cannot be removed by regular means. This app was designed so you cannot delete it by going into settings and uninstall it. The only way to uninstall it is to plug your phone into you computer and manually delete it but I do not know where the files are to do it and I advise not to do it. You could accidentally delete files used to make the phone run so it is a risk if you do not know what you are doing.