Mobile number or email address is a Non-Core Field and can be amended from the taxpayer’s account on the GST Portal.

  1. Login to GST Portal

  2. Go to Services > Registration > Amendment of Registration Non-Core Fields

  3. Select tab Promoter/Partner or Authorized Signatory and make required change to mobile or email

  4. Click on verification tab, select authorized signatory, enter place and sign application using DSC, E-sign or EVC

  5. Success message is displayed and copy of acknowledgment is sent to earlier registered email and mobile

Read more - How to change mobile number or email on GST Portal