The back button, also known as the hardware or on-screen Back button in Android devices, is a navigation key that can be found at the bottom of most Android devices.
It is a navigation tool typically at the bottom left corner that appears as a back arrow pointing to the right. This is used for navigating away from any open app or menu item within an app. It does not close out of an application completely, but rather just goes to another page in it instead. Most applications will show pages by default with “back” and “home” buttons (the latter being generally up above).
The primary function of this button is to return users to previous screens when they have scrolled through their current screen and want to go back. This enables them to use it for scrolling up one page from where they are currently located without having to scroll all the way down again with their fingers.
Another major functional purpose of these buttons is not only being able to go backwards by clicking on them but also going forward if you’re in your messages list and need more conversations sent/received from someone who isn’t there yet (or has been blocked), then tap next to the message you want to see and it will take you there.