An epilogue is a nice way to let your readers know what happened to your characters after the story has ended—particularly if the end of the book is ambiguous in any way. It can also be a chance for you to show how the events of the entire story impacted the characters—the lessons they learned, and how they have grown.
What does the epilogue signify about the lives of the characters?
A compelling epilogue shows you how some of your favorite characters fared or their future lives. It might tell you how a marriage is going or how they fit in at their new job. Find out how they used the lessons they learned in the story to grow as a person.
Is it important to read the epilogue of a book?
If the epilogue contains necessary information, what you have is an unresolved ending, and you should revisit whether or not you've written the strongest ending possible. Your reader should be able to close your book at the end of the last chapter and have read a complete ending—to have closure without reading further.