All I want Is a SIMPLE ANSWER TO MY QUESTION WHICH i HAVE NOW ASKED 3 TIMES!!! SIGN IN INFO. WHY IT NO WORK?

First if you say yours is the most visited home page for emails then I would recommend thet use Hotmail or Outlook, much better. Trouble is I have been saddled with having a Yahoo address. NOW MY QUESTION FOR THE THIRD TIME. NOW LISTEN CAREFULLY. WHY WHEN IT SAYS i DONT HAVE TO SIGN IN EVERY TIME THAT, THAT IS WHAT I AM BEING ASKED TO DO???????????? my next question , why is sch a famous site taking ages to answer this basic question. haing to sign in each time is a real pain in the ***!!!!!!!!!!!!!!!!!!!!!