The charge is changed to accepted when the store's owner clicks accept when landing on confirmation_url, so it is an interactive action the merchant has to perform. Once that happens (either the charge is accepted or declined) Shopify would redirect back to your app with the status, and you can either activate it (if accepted by merchant) or retry it (if declined).
More information and an example of a complete flow here - https://help.shopify.com/en/api/guides/charging-for-your-app/guides/implement-billing-model
Thanks for replying.
Recurring billing charge status was changed, but how can I activate the billing method for a merchant ?
I have created my app with the laravel framework, when it was redirected to my app then it will gave me not found issue for my redirected url, if you have any laravel shopify app reference then please share it with me. Again thanks for your help.