Currently, banners and icons can only be changed on desktop, check out more info about channel art here: https://yt.be/help/sg6D You can also find the steps on how to manage your channel icon here: https://yt.be/help/bmzM . Hope this helps!
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more