How to change the wallpaper on Cubot devices

Cubot J10 Cubot J10
Cubot KingKong 7 Cubot KingKong 7
Cubot KingKong 5 Pro Cubot KingKong 5 Pro
Cubot C20 Cubot C20
Cubot J8 Cubot J8
Cubot KingKong CS Cubot KingKong CS
Cubot Note 7 Cubot Note 7
Cubot P40 Cubot P40
Cubot Note 9 Cubot Note 9
Cubot Max 3 Cubot Max 3
Cubot KINGKONG 5 Cubot KINGKONG 5
Cubot KingKong Mini 2 Cubot KingKong Mini 2
Cubot X30 Cubot X30
Cubot Note 20 Pro Cubot Note 20 Pro