You can check the status of your green card renewal application to see if it has been approved by following these steps:
Go to the USCIS Case Status Online page.
Enter your 13-character receipt number in the space provided. You can find this number on the Notice of Action (Form I-797) that you received after filing your application.
Click on the "Check Status" button. The next page will show you the current status of your application.
Alternatively, you can sign up for E-Notifications using Form G-1145.