Hi Narendran j,
Please refer to this documentation it might be helpful to you.https://medium.com/mendix/mendix-how-to-add-font-icons-465e2a03884
Hope it helps!
On your native login page (find it via Navigation->Native mobile) you have a textfield for username and one for password. Give both of them a classname, place an image below the username, place a button with an eye below password. Create two input groups, one surrounding username and the image, one surrounding password and the button. Have a look at https://getbootstrap.com/docs/4.0/components/input-group/ to add the necessary classes and styles to get the image and the button inside the textboxes.