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 1^st person to indicate offer or suggestion and with the 3^rd 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)

Compare:

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.)