DNS Changer is the easiest way to change DNS. It works without root and works for WiFi and mobile network data connection.
Supported Android
(4.1 and up)
Ice Cream Sandwich (4.0 – 4.0.4),Jelly Bean (4.1 – 4.3.1),KitKat (4.4 – 4.4.4),Lollipop (5.0 – 5.1.1),Marshmallow (6.0 – 6.0.1),Nougat (7.0 – 7.1.1),Oreo (8.0-8.1), Pie(9.0)