Hi Moshe and welcome.
If, by the lack of a back button, you are referring to, for example, a link in an email opening your browser, you can get back to your email client by four finger swiping across the screen. This action cycles between open apps.
If, by the lack of a back button, you are referring to, for example, a link in an email opening your browser, you can get back to your email client by four finger swiping across the screen. This action cycles between open apps.