Adobe officially pulled the plug on mobile Flash in 2012. Since Android 4.2.2 (Jelly Bean) was released after this transition, it never had a native, pre-installed Flash plugin. Furthermore, modern browsers like Chrome and Firefox have removed the architecture required to run Flash plugins entirely. To get it working today, you need a specific combination of a legacy APK and a compatible browser. How to Download and Install the Flash APK
A browser specifically designed to handle Flash content on older Android builds. Important Security Warning
Once installed, go to Dolphin Settings > Web Content > Flash Player and set it to "Always On."