2014年9月19日发布的iphone 6 Plus有着比iphone 6大的5.5英寸屏幕。
my i phone 6 plus teach and app are woking by it self without teaching to screen its typing and app are opening by it self
I would suggest you try replacing your screen, that would be the first thing to do.
If that doesn’t work, then it may be a logic board issue which would require someone who can microsolder to help you out.
iOS repair by Scott
look at microsoldering.com for a description of touch IC disease and see if your phone fits this description.