Default to Billing Address as the Shipping Address to avoid fraud

Hello Madmax3,

Authorize.net has excellent fraud prevention options for you to select, such as the billing address and shipping address must be matched before processing the order.
This is a way to prevent a person from winning a chargeback if filed after placing the order or another scenario, someone who has obtained/stolen a credit card or card number and using it to place an order and shipping it to a location of their choice.

Shopify does not offer this feature.

Best of luck to you.