1 directly on axis website
2 on the axis app
3 on Google pay, scroll to bottom, click on the trophy called "rewards" and see if you have the offer
If not then check credit report on Google and wait.
Alternatively try out Google pay of parents/siblings.
There was no pattern to spending I suppose. My number registered on Google pay for not have any credit cards on the number. That's why I guess I got 2 year free