Simple Future tense is used to describing job or action that will to do (happened) at future.
Formation of sentences
1. Positive( + ) S + shall/ will + V1
Ex :- I shall clean the room
- We will go to schoolOr( + ) S + be + going to + V1
Ex :- I am going to play tennis- He is going to write a story

Notes : "shall" just can use for subject "I and we"
2. Negative( - ) S + shall/ will + not+ V1
Ex :- I shan't buy a shirt- He won't clean the room
Or( - ) S + be + not +going to + V1
Ex : I am not going to give a present

Notes : shall not = shan't, will not = won't
3. Interrogative( ? ) Shall/ will + S + V ?
Ex : Will we playing tennis ?
Or( ? ) Be + S + going to + V ?
Ex : Is she going to write story ?