The Promo Code can be used during the new Bitrix24 account creation only, there is no way to activate the code after the account has been already registered.
Please click "I have a coupon" option in the new Bitrix24 creation form:
Just in case you have added your promo code to the corresponding field but the special offer hasn’t been activated (e.g. additional storage space hasn’t been added), please contact our Helpdesk with your Bitrix24 account name and promo code details.
