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The App Store sometimes asks for billing information even for free apps, even if you don't have any intention of making in-app purchases. This is because the App Store uses billing information to verify your identity and to prevent fraud.
In your case, the App Store is asking for your billing information because you have already downloaded PUBG Mobile in the past and made in-app purchases. When you try to redownload the app, the App Store is checking to make sure that you are the same person who made the previous purchases.
If you are getting the error message "No sufficient balance", it means that the credit card or debit card that you are using does not have enough funds to cover the cost of the in-app purchases that you have made in the past.
To fix this error, you need to add a credit card or debit card with sufficient funds to your Apple ID. You can do this by going to Settings > Apple ID > Payment & Shipping and then clicking on Add Payment Method.
Once you have added a credit card or debit card with sufficient funds, you should be able to redownload PUBG Mobile without any problems.