Hi @ArhamAli ,
Thanks for reaching out.
If you develop and publish apps using ArcGIS App Studio and your developer license subscription period expires, your apps should continue to work. However, you will lose access to technical support and software updates, and you won't be able to create or publish new apps until you renew your subscription.
When you make an app using ArcGIS App Studio using the Make tool, the app becomes a standalone application that is exported in a binary installable (.apk for android, .ipa for iOS, etc). Once you publish the app, it's not connected to the App Studio software or your developer license subscription. This means that the app should keep working fine on devices where it has been installed, even if your developer license subscription expires.
It's important to keep in mind that the app may depend on other ArcGIS services or software components that could require a valid license to function properly. If your subscription for these services or components expires, it could impact the functionality of your app.