Make sure you are login or have access to both Google Play Console https://play.google.com/apps/publish (you have to access as owner) and Google Developer Console https://console.developers.google.com/apis/dashboard these accounts required for the next step and make sure your accounts are the same google/gmail account for accessing both.
1. Open Google play console - Developer Account - API Access
If you don’t have any project, just Create New Project, and after new project being created the result is shown as below Next, just click the newly created Linked Project “Google Play Android Developer” it will open new tab in your browser for your Google Developer Console
2. Enable APIs and Services
In the step before just click ENABLE APIS AND SERVICES In Mobile section - select Google Play Android Developer API
And Click Manage Button
Next Create credentials by selecting Menu Credentials in the left, see screen above.
Press “Create credentials” button and then select Service account key and see next screen and fill required information
Just click create and Don’t forget to save the JSON file, this file required for web developer to access our google play account through the google developer console service account
3. Grant Access Service Account
Back to your Google Play Developer Console and open like in the step 1 before or if you already opened the tab just refresh your browser and the page will change like this
Just click GRANT ACCESS the service account, this service account is the result of our step2 before. And then select the required role. For our case is “Administrator” role for service account, see screen below:
And after finished select the role. Just click add User in the Bottom of popup screen
After that we will see the newly created service account can access our google play