The procedure to reactivate an account that was deactivated at the client's request is as follows:

Online

The Zerodha account can be reactivated online if a mobile number is linked with the Aadhaar. Submit the e-signed reactivation letter (PDF) by creating a ticket. To learn how to sign a document digitally, see How to esign documents on Digio?

Offline

Print the reactivation letter (PDF), fill up the details, sign and courier it along with a self-attested copy of the PAN card & address proof (any one: Driving Licence, Voter’s ID, Passport, Aadhaar) to the following address:

Zerodha,
153/154, 4th Cross, J.P Nagar 4th Phase,
Opp. Clarence Public School,
Bengaluru - 560078

The account will be reactivated within 7 working days. The client ID will remain the same as before, and a new password will be sent to the registered email address.

If the trading account was deactivated and the demat account was closed, then the demat application (PDF) must be filled out and submitted to the address mentioned above. The account opening process must be redone if the Zerodha account is closed and not deactivated. See How to open a Zerodha account online?