Apk has not devolped

#1

there is no apk present in my output folder

#2

There is really no reason to dig through paths; the IDE hands it to you (at least with version 1.5.1).

In the Build menu, select Build APK:

Android Studio Build Menu

A dialog will appear:

Android Studio APK Generated Dialog

If you are using a newer version of Android Studio,

prompt to locate your APK file

Clicking the Show in Explorer or locate link, you will be presented with a file explorer positioned somewhere near wherever Android Studio put the APK file:

File explorer after clicking the link in the APK Generated dialog

But in Android Studio 3, when you click locate, it puts you at the app level. You need to go into the release folder to get your APK file.