
To sign your app using Android Studio, and export an existing app signing key, follow these steps: If you don’t currently have the Generate Signed Bundle or APK dialog open, click Build > Generate Signed Bundle/APK. Then click Create new button to create new keystore file. In the next popup, select APK and click Next button. And select Build > Generate Signed Bundel / APK. There's a chance this is also causing an issue. Additionally you probably want to remove debuggable true from your release config, as debuggable builds can't be uploaded to Google Play. When generating an APK, make sure both the signature types are checked, otherwise Fabric (and other places) may not recognise it as signed. After that the menu for generate signed apk will now be available.

and continue till it says synced successfully. You need to close your project and import it again, wait for notices for a possible needed update ie: SDK, sdk tools etc. This happens if your android project did not synced successfully. Generate signed apk Android Studio not showing
