Go to Music > Sidebar to tap Custom skins or Themes (Slightly different countries or regions)

Custom skin:

You can tap Personalized skins > more ＞ > My skins ＞ Customize, to choose picture as your skin or choose the beautiful skin provided by the preset；

Custom player:

You can tap Personalized player > more ＞ > My players, to choose a custom player for different experiences

Figure 1.

At present, this function is only supported on mobile phones, not on pad，so if your mobile phone is Mate 20x, you need to go to Settings > Display, increase the Text size and Display size in Text and display size and make sure the Screen resolution is set to HD+.