If you are using an older iPhone that doesn't support the latest iOS, or if you are trying to get Netflix on a device that doesn't have the official App Store (like a developer-focused device or, in rare cases, specific Android TV boxes running iOS emulators), you might need the IPA file to manually install the app.
The legitimate and recommended way to obtain the Netflix app on an iOS device is through the App Store. However, there are scenarios where users might look for an IPA file, such as: netflix ipa