What is the effect of typing letters?

The effect of typing letters is similar to that of flashing letters. I don't know if I understand. That is, the information sent to users can be directly displayed on the screen of their own mobile phones, and the normally used mobile phones can be directly displayed on the main screen interface. The use of "Spring Letter" has obviously improved the reading rate of information. Whether playing games or watching videos, users must see it in various scenes.