1) Used to refer actions or events that will happen in the future .
I’m sure it will rain this afternoon.
2) Used with will to make predictions or refer to events which we think are highly possible in the future.
Manchester United will beat all the other teams to win the FA Cup this year.
3) Used with will to refer to something which we decide to do at the time of speaking.
Don’t worry, I’ll worry be careful.
4) Used with going to for actions which we have already planned to do in the future and events which we think are possible in the future.
Asian share markets are going to perform better at the end of the year because of brighter prospects in the US economy.