Have gone into language and input and selected default keyboard, then selected set up input methods, it then says Samsung Keyboard multiple languages, it shows it is on, but it is grey, not blue.
Welcome to the forums. You can try loading a different keyboard on your phone to see if that can help. You can log on to Play on your PC, select a different keyboard, click install, and wait until it send to your phone. Depending on your internet speeds, this should be relatively quick.