for example: I will take a walk. This is something planned and definite. I am definitely going on this walk. I will take this walk. I will phone my friend. I would take a walk, if.... This is something I may do, may not do, has some conditions added to it - for example: I would take a walk if the weather improved. She would come to your party if you invite her. I would phone my friend if I could find my phone. It would be fun to go on holidays, but I don't have the money right now.

They're both hypothetical, but "will" is used for sure future events. "I will..." means you have an intention to act upon. "Would" is a kind of past form of "will". It's used for conjecture (ie. when you're not so sure), second and third conditionals (unlikely/impossible results), and even reported speech: "I'll help you" she said. --> She said she would help me. The conjecture element of "would" applies to politeness and formality in English, eg. "I would like..." and "If you would be so kind as to..."

Thank you

'will' denotes that I will do something. I will buy a boat next year. 'would' is used in the conditional. I would buy a boat next year if I have enough money.

Will is used for future, would is used for fact that didn't happen. It is fun on holidays (present) -> It will be fun on holidays (future) It is fun to go on holidays (present/fact). -> It would be fun to go on holidays (open option of fact that didn't happen so far)