Address Verification System (AVS) is controlled through your payment gateway settings.
AVS is setup to prevent fraudulent transactions from being processed. You can control the threshold for your AVS declines in your payment gateway online interface.
You can set your Gateway to decline transactions based on street address, zip code, and other combinations that don?t match the cardholders name or billing address. Even if the transaction would normally be approved it could decline.
If you are seeing declines due to AVS mismatches, check your billing address fields in Salesforce for completeness and accuracy.
More information can be found here: