"Add family payment method" is a feature provided by Google and is not controlled by Mobile Fence.

Below is the help information related to this feature.

• Use a family payment method on Google Play → https://support.google.com/googleplay/answer/6294544?hl=en

• Using paid Google Play apps for free among family members → https://m.blog.naver.com/PostView.nhn?blogId=erke2000&logNo=221445984868&proxyReferer=https:%2F%2Fwww.google.co.kr%2F

• Signing up for the Google Play Family Library → https://m.blog.naver.com/jungah825/221857723540