Can I restrict shipping to a specific address or customer?
You can restrict shipping to a state or country; you cannot prevent shipping from being calculated on an order whose ship-to address is valid in your current shipping tables. Please see Q.6120 for further instruction on how to restrict shipping to a specific country and Q.375 to restrict States.
If you want to restrict a customer from ordering at all, you could make their customer record Inactive. Go to the customer record, click the edit pencil and uncheck the box next to ‘Active’. They will not be able to log in and will see a message indicating their record is Inactive if they try to log in. You cannot delete a customer once they have placed an order.
Also, you do have the opportunity to adjust shipping in the order before funds are captured. Click the order number, click the Edit button next to Line Items, click Override and enter new shipping fee.