Difference between WILL and Shall

 In old English native English speaker strictly followed this rule but with the change in time, the rule also changed or at least strictness became mild :) 

In past native speakers used Shall with first person pronouns i.e., " I" and "we". For example,

I shall meet you at the bus station.

We shall have dinner together on Sunday. 

Interchangeability: In many cases, especially in contemporary usage, "shall" and "will" are used interchangeably without significantly altering the meaning of the sentence, especially in everyday conversation. However, the choice of "shall" can add a touch of formality or emphasis in certain contexts.

Emphasis and formality: In modern English "shall" is only used when the speaker wants to add emphasis or when he wants to act formal.

In modern English, especially in American English, "will" has become more commonly used across all persons for future actions, while "shall" has seen a decline in usage. "Shall" is sometimes used in formal writing or in certain contexts to convey a sense of formality or in polite suggestions, invitations, or offers.

• "Shall we dance?" (polite suggestion)
• "I shall submit the report by Friday." (formal statement)

• "I shall meet you tomorrow" (An emphatic statement, with an emphasis on "meeting")
• "I will talk to you tomorrow." (simple future, without an emphasis on "meeting")