# replacementRange() Returns the range in the client document that the text should replace. ``` func replacementRange() -> NSRange ``` ## Return Value The range to replace. ## Discussion This method is called by [`updateComposition()`](/documentation/InputMethodKit/IMKInputController/updateComposition()) to obtain the range in the client document where marked text should be placed. The default implementation returns an `NSRange` object whose location and length are `NSNotFound`. That indicates that the marked text should be placed at the current insertion point. Input methods that insert marked text somewhere other than at the current insertion point should override this method. An example of an input method that might override this method would be one replaces words with synonyms. That input method would watch for certain words and when it detects such a word it would replaced the word by marked text that was a synonym of the word. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)