Shall and will
According to grammar rules the modal auxiliary shall is used in the first person and will in the second and third persons to talk about future.
I shall start the work tomorrow.
He will start the work tomorrow.
You will start the work tomorrow.
Shall can be used with second and third person pronouns to express a command, threat or promise.
You shall leave this place at once. (Command / order)
If you make a noise, you shall be punished. (Threat)
Note that in modern English there is a tendency to use will in all persons to indicate future tense or command or threat.
In interrogative sentences shall is widely used with the 1st person to indicate offer or suggestion and with the 3rd person to know the desire of the listener.
Shall I get you a cup of coffee? (Offer)
Which book shall I buy? (Asking for suggestion)
Note the use of shall and will in the following sentences.
The college will remain closed. (=It is certain that the college will remain closed.)
The college shall remain closed. (= It is ordered that the college shall remain closed.)
You shall not harm the child. (= You are ordered not to harm the child.)
You will not harm the child. (= You are not going to harm the child.)