We use will as a modal verb expressing the future tense , would as a past tense of will.Originally Posted by Ruth Winett
For instance , he said he would be away for a couple of days.
It also expresses the conditional mood " indicating the consequence of an imagined event or situation "
He would lose his job if he were identified.
I would is used to give advice as in "I wouldn't drink that if I were you".
It can express a desire or inclination " Would you like some water?."
It expresses a polite request " Would you pour the wine, please?".