The tense used to talk about things that will have happened before a future event is the future perfect tense.
The future perfect tense expresses an action that will be completed before a specific time in the future. It is formed by using “will have” + past participle.
For example:
“By the time I arrive at the party, the guests will have already left.”
“By the end of the year, the company will have launched three new products.”
“When you return from your trip, I will have finished painting the house.”
In these sentences, the actions of the guests leaving, the company launching new products, and the painting being finished occur before the future events of the speaker arriving at the party, the end of the year, and the speaker’s return from the trip.
The future perfect tense allows us to describe actions that will be completed prior to a future point in time, helping to establish the chronology of events and show how different actions are sequenced relative to each other in the future.