Will = intention, certainty, and future || Must/Should = necessity, obligation, and advice || Can/Could = suggestion and ability || Would = consequence and hypothetical situations
To signal any intention or any activity in the future, WILL is used. MUST (which is stronger than SHOULD) is used to express what is necessary to do. CAN or COULD can be used to make suggestions or talking about the potentials. WOULD is used to predict the outcome of an idea or a solution.