The answer to this question is a little bit complicated. First of all, there is no specific rule that dictates the format of bingo cards.
Second of all, the design of a bingo card is usually based on the theme or style of the game it is used in. .
For example, if you are playing a traditional bingo game using paper bingo cards, it is likely that the cards will be predominantly white with black numbers. However, if you are playing a modern game using electronic bingo cards, the cards may be brightly coloured and feature various animations and graphics.
Ultimately, the most important thing to remember when it comes to designing bingo cards is that they should be complementary to the game itself and make it as fun and enjoyable as possible for players.