Play Store is a marketplace where Android app downloads are provided by Google. The Android developers, many of which upload their works to the Play Store, although many choices of Android app stores like Amazon, Mobogenie, etc. To publish apps to Play Stroe there are some things to be prepared before apps can actually be published. We need Key / fingerprint to our application, this key is called release key. Release key is required for apps to be published in the Play Store

How to Create Keystore and Release APK

The first step is to open the project you want to publish.
Select the Build menu -> Generate Signed APK. After that will appear dialog box "Generate Signed APK". Here we will create a new Keystore file (If there is no need to create new). Keystore can be the identity of our application. Keystore is usually used in the process of file authentication and data communications. Keystore can be likened to our signature for every application we have ever made. But the thing to remember is: We must use the same keystore when it will update the app (replace the old version apk with the new version apk).
Click the Create new button. Then click the (...) button next to the Key store path box to determine the direction of the location of the keystore.
Fill in the fields according to the required information. Then click Next.
Next we determine the location where the APK file will be stored. Build Type Release. Click Finish.
Take some time, so the box appears as below, meaning you succeed.