i have my developer google play account and i setup ed merchant account
in my app i have in app purchase plugin when i tray to add in app product google tell my to in app billing permission to my app
when i search for add pilling permission i found i must have play_store_key
any help please
sorry ,
i found the solution under Services & APIs after upload my APK File
Thanks 
i still face problem **Your app doesn’t have any in-app products yet. **
To add in-app products, you need to add the BILLING permission to your APK
i already added the pilling permission and uploaded apk
how to solve that ?
I ran on the same “BILLING permission” issue today. Wasted few hours googling around and reading docs and tutorials.
Finally I found a solution, so I’m posting it here. Maybe I’ll save someone some time. 
There are a lot of articles and Stack Overflow answers out there, telling you to add
<uses-permission android:name="android.vending.BILLING" />
or
<uses-permission android:name="com.android.vending.BILLING" />
to your AndroidManifest.xml. But it won’t do the job any longer. It was required before 2017, then Google changed some things and now it’s obsolete.
What you have to do now to get BILLING permission in your app, is to go to your
/android/app/buld.gradle
file and under ‘dependencies’ add
implementation 'com.android.billingclient:billing:2.0.2'
And you can find the latest version of the library here: Billing Library release notes