You're ready to type the end. Allow yourself that moment of relief and of joy. The book is finished, but you need to check one thing. You need that scene packed with emotion. All was lost. Then the character decides to fight. The scene before you write the end needs to show this. Someone or even more than one character will win and someone or more than one will lose. this climax scene needs to set all right with your world - the fictional one. Real world don't always act in this way.
Show the winning character in all his or her glory. The lovers are reunited. The detective catches the villain. The evil wizard is taken down. Show the villain in defeat as well as the winners in joy. The reader will be happy to see the end of the journey. Doesn't mean this story will end happy ever after or even happy for now. The ending needs to show an ending that satisfies the reader.
There is one thing. Make sure you tie up all the loose ends. If there's a subplot make sure the reader sees that it has ended. If you've laid clues throughout your story make sure they're all tied up so the reader doesn't react with a well the story's over, but what happened to X or Y. Once this is completed you can type the end and then set about editing before you send the story off.