This is an input uppercase Latin alphabet symbol with the uppercase letters ABCD displayed in order. It is used when switching to uppercase in the soft keyboard ⌨️
. The background color of it is black and white on some platforms. And there are only three letters on the symbol on Facebook. It’s used when someone is facing a multiple-choice question in English learning ✏️
. It may also be used when arranging seats or assigning them in order.