How do I add billing permissions to my APK?

I've just uploaded my APK to Google Play and I when I try to set up the IAP's, I get this on my developer console:

"To add in-app products, you need to add the BILLING permission to your APK."

Is this something I need to do in Stecyl?

Go to settings > mobile and check the box that says in app billing

I don't see it...

it's ok , found it

Forgot to mention under the monetization tab i believe haha