Go to Gear in the top right corner, and select Shipping and Returns under Tools.
Select +New shipping service.
Name your shipping service and select the country and currency you want the shipping service to be applied to
Next, you’ll have to enter delivery times. You can either choose to show custom delivery times or set a range of delivery times.
Setting a range of delivery times involves a few more steps:
Order cutoff time: It is the time of day by when the orders must be placed in order to be processed that same day.
Handling time: It is the time between the order being placed and put out for delivery during business days. You can enter 0-0 if you offer same-day shipping.
Transit time: It is the time it takes for the carrier to deliver the order to the customer.
Put in your shipping costs
After you’ve got all of your shipping settings in place, you can test if prices are accurate by going to the products page in Google Merchant Center.
Select a product, and when you scroll down a bit, you’ll see the price.