How does Tik Tok's blogger use 3D rainbow font to make his signature an avatar?

In Tik Tok, bloggers use three-dimensional rainbow fonts to get their signatures as avatars, as shown below.

1. Open the Tik Tok homepage and select the lower right corner.

2. After entering the personal homepage, click on the nickname above.

3. Then click on the name.

4. When you come in, choose to enter the word rainbow with the keyboard, and you will find a rainbow picture behind the rainbow Chinese characters. At this time, click on the rainbow.