Talkback is a screen reader primarily for people with blindness and low vision. It allows interaction with the device using spoken feedback. In this mode, you need to quickly touch the button twice to choose the button.
Please go to “Settings”->”Accessibility”->”Talkback”, touch the toggle to turn on/off it.
To navigate using Talkback:
-Swipe right or left to move between items
-Double –tap to activate an item
-Drag two finger to scroll