Bubbles and squares
White bubble letters come in capitals, lowercase and digits. Black bubbles and squares only exist as capitals in Unicode, so lowercase letters become capitals in those styles. On some phones, a few black squares (🅰 🅱 🅾 🅿) appear as colorful emoji.
Use it with care
Screen readers may read these characters strangely or skip them, and search won’t match them to normal words. Keep the important words, like your name or your shop name, in plain text somewhere too. Very old devices may show empty boxes.