Go to Settings > Security and toggle on Unknown Sources . This allows you to install apps from outside the Google Play Store , which no longer supports KitKat.
Try a different iRoot version. For example, if v2.x fails, try v1.8.9. Alternatively, use the PC version of iRoot (Windows 7/10) instead of the APK. Download Iroot Apk For Android 4.4.2
Before downloading, it’s important to understand why you’d want to root a KitKat device in the first place. Go to Settings > Security and toggle on Unknown Sources
Use Titanium Backup to save full app data, which is not possible without root access. How to Download and Install iRoot APK if v2.x fails
: Locate the downloaded file in your Downloads folder using a file manager and tap it to install.