You can track the status of new registration application using ARN, once Part B of new registration application is submitted on the GST Portal, post-login (using TRN).
To track status (with Temporary Reference Number (TRN)) of your new registration application, perform following steps:
1. Access the https://www.gst.gov.in/ URL. The GST Home page is displayed. Click the Services > Registration > New Registration option.

2. Select the Temporary Reference Number (TRN) option. In the Temporary Reference Number (TRN) field, enter the TRN received. Enter the Captcha details and click the PROCEED button.

3. In the Mobile / Email OTP field, enter the OTP you received on your mobile number and email address. OTP is valid only for 10 minutes. Click the PROCEED button.
Note:
OTP sent to mobile number and email address are same.
In case OTP is invalid, try again by clicking the Click here to resend the OTP link. You will receive the OTP on your registered mobile number or email ID again. Enter the newly received OTP.

4. The My Saved Application page is displayed. You can check the current status of the new registration application under Track Application Status section under Status column.

Note: Listed below are the different status types for New Registration Application:
Pending for Processing – When new registration application is filed successfully and is pending with Tax Officer for Processing