When setting up your shipping and/or payment options, you can customize them with your Geo Zones, or sets of geographical regions. For example, let's assume you live Texas, USA. You offer flat rate shipping domestically, but for international orders you would like to use weight based shipping. You also only accept in state checks. You would set up one Geo Zone for the USA, and then a separate Geo Zone for Texas. You could then apply flat rate shipping to only orders from the USA and only accept checks from orders from Texas.