You can change your name using the Rename Lord item, which you will have once you reach castle level 2.To change the name, click on the Lord avatar on the left corner of the screen, tap on the pen icon, then choose at least 3 characters and avoid using special characters.
The Lord Avatar is what will be displayed for players. And you can change it by clicking on the Lord avatar on the left corner of the screen, tapping on the two arrows on the Lord avatar, then choosing "change avatar'' and clicking one of the avatars available, or you can upload it from the gallery or take a photo.
The Lord Image is what will be displayed in the player's info. To change the lord image, click on the Lord avatar on the left corner of the screen, tap on the two arrows on the Lord avatar, then change your image by choosing one of the heroes' avatars available.