Migration completion procedure enables provisional ID taxpayers to obtain a GSTIN via portal application and GSTN mapping. Eligible taxpayers who received only a Provisional Identification Number must apply via FORM GST REG-01 on the GST portal, obtain a new GSTIN, ARN and access token, and then e mail the new GSTIN, access token, ARN and old GSTIN to the GSTN migration address so GSTN can map the new GSTIN to the old PID and the taxpayer can complete first time login to generate the registration certificate.