The difference between shall and will can be quite complicated but in general A)Shall is used with 'I' and 'we' to make a suggestion or ask a question that you want the other person to decide about. 'Shall we go to the cinema this evening?' 'What shall I get for dinner tonight? (you can't use 'will' for this) B) In British English 'shall' is used with 'I' and 'we' to say what you will do in the future. 'We shall be away next week. 'I shall be busy tomorrow.'(You can use 'will' instead). Some people consider this usage rather formal. C) In formal and perhaps old fashioned English 'shall' is used to emphasize something will definitely happen. 'The truth shall set you free.' (You can use 'will' instead by putting emphasis on the word 'will') D) In formal English 'shall' is used in official documents to state an order, law or promise. 'All payments shall be made in cash.'

I am not a native, but people told me that "shall" is out of date word so that's why people rarely use it. but people use it to asking someone to do things with them, like "Shall we dance?" "Shall we go?" ,,, but as ur teacher said,, it's also correct to use it as alternatives of "will" "I shall come to your party" "I will come to your party"

by laws or directives, the word SHALL means you are obliged to do something. somewhat mandatory. or it can also means, you will definitely do it. like in the phrase, "the hearing of the famous criminal shall be made public" -this means it is mandatory. "i shall return" - this one means you are definitely going back. WILL as an auxiliary verb to is,are..etc means you are going to. "i will return" you are going to return.

will and shall are modals used to express the simple future will is used with in all persons while shall is used with first person(I and WE) i will help you. mum will help me. they will help you. i shall help you. we shall help you.

Shall is technically correct, but no one ever writes or says shall unless they are being ironic. Most people today, at least in America, would agree that "shall" is archaic.