https://www.desidime.com/discussions/jiomart-gift-card-needed?page=1#post_8767713
Either you can trade in the Trading section, or simply buy JioMart Gift Card with the credit or debit cards on which offer is going on currently.
Remember that you can only buy gift cards for other accounts. So, if you need Gift Card in your account, then purchase it from other account, giving your number as the beneficiary account.