Congratulation!!!
Axis Airtel was my first credit card ever, I applied it the very first time it launch, I was lucky and got it without any income document and approved.
I also started my Axis Credit card journey with 15k limit.
Applied for Airtel Axis Credit Card, instantly approved got 15k limit, Date: Feb 2022.
My First Unsecured Credit card, but the limit was disappointing. But the card was super useful as all my devices are Airtel related(Sim, fiber...
You don't need invite, try this link on your mobile phone which has the Airtel Thanks app.
Link:- https://www.airtel.in/airtel-axis-credit-card
I did not have any invite, it worked for me, got this card without any income proof 6 months ago.