Hi,today I was searching how to get ok google everywhere and found a solution.make sure google search app is up to date and just search for ok google everywhere using your google search option and get ok google everywhere option I don't know how it works but google is giving this feature on the basis of accounts.It worked on my rooted galaxy note.this is not my work unfortunately I can't remember the name of the person who found this solution.Just give it a shot .It may work for you too....