Retrieving and Editing a Given Word in the Text File in the Console Application in c#

Retrieving and Editing a Given Word in the Text File in the Console
Application in c#

I have a text file with many English words and dates stored in it.
APPLE Pineapple orange
sunflower Grapes LOVER
Prize mettle KITTEN
Is there a method in c# file stream or array list where i can just
retrieve the word by just typing it.
Ex: Console.WriteLine("Enter The Word That needs To be Retrieved");
String input = Console.ReadLine();
Since c# is a case sensitive language, is there a way, if the user types
kitten the word KITTEN gets retrieved. If i want to edit it like
Console.WriteLine("Do you wish to edit");
and i type LOVER but i want to edit the word as loving. How do i
go about it?