Undo typing touch screen icon, repeatedly pops up with each touch

My iphone 6 plus suddenly developed an issue where everytime I try and type a email or a text, once I touch any letter or number, the touch icon (photo attached) that has the words < Undo Typing, & below that word, <Cancel/Undo> Will pop up. As soon as i touch cancel on the offending icon,, then i touch the next letter im typing, it pops right back up, touch a leter, pops up. Can anyone tell me what part I need to either repair or replace. Or what area of the inside to inspect for a loose connection before going On.