Student or Learner
some one please explain me she will have come.
***** NOT A TEACHER *****
"Will have" + past participle is called the future perfect.
Does this dialogue help:
James (speaking at 1 p.m.): Where is Mona?
Mona's mother: She's not here.
James: I need to see her. It's important.
Mona's mother: Come back at about 5 p.m. I'm sure that she will have come home by then.
The future perfect is not used very much by most Americans. They often express the idea in other ways: I'm sure that she will be home by then.