What is the Future Perfect Tense?
pattern = will + have + past participle
Future perfect - is used to show something that will happen before a future event happens or takes place.
I will have eaten my pizza by lunch.
By next week, she will have given birth.
I will have graduated by the time she gets married.
Using the word by gives the future event, by next week, by next year, by tomorrow, are all events/times in the future.
We use the future perfect to show something that will happen by that time.