First, you should’ve already signed up for an Android Developer account and logged into the Google Play Console to get a Google App Signing/Upload key, which is a topic for another blog…
Also, every time you update your app, you MUST update your version code or the app upload won’t work when you get to the Google Play Console. If you’re making an app in Unity, go to File > Build Settings > Player Settings, Other Settings > Identification and change the Version and the Version Bundle Code. This is also where you set your Package Name which MUST match your keystore settings from when you set up your upload key.
By the way, you can also “cosmetically” set your Company Name and Product Name in the top two fields of the Player Settings menu. Actually this Project Name field is only naming the project folder, which cannot be a duplicate of a previous name in the same location or it’ll fail to save.
Right now the app bundle is in debug mode. You need to sign your app bundle in release mode in order to publish it in the Google Play Store.
To do this, you must first choose your Build platform in Unity with the Export Project setting (Android in this case). Then import your project into Android Studio with the import project (Gradle…) option. From there, you need to select Build > Generate Signed Bundle… You want to select Bundle (not APK) for Google Play Store apps.
Choose your existing key store path, which should’ve been generated when you created it from the Google Play Console instructions mentioned at the beginning. You may need to contact Google Play Support to help set this up like I did. It might take a few hours for them to respond.
Hopefully you remember your key store password, so you can access your existing key alias. Now enter your key password. You should write them all down somewhere you’ll be able to find them. Select Release mode. Hopefully, everything works. If so, “Gradle Invocation Finished” will pop up on the top right of the screen with links to locate or analyze your bundle at the bottom right of the screen.
If so, go to the Google Play Console > App Releases and then do a Production release, and upload the new or updated version of your app with the updated release name. You’ll need to go to your bundle folder, open the Release sub-folder, and select the file with the “.aab” extension.
Once your app is uploaded and approved, you’ll probably get an email from Google. The whole process took me about 5 days from beginning to end the first time. I’ve heard that updates are faster.
P.S. Although it’s free to publish apps on the Google Play Store, publishing apps as an Apple iOS developer on the App Store costs $99/year for the license…