Hi @RL3 are you using Square Online?
To get started with shipping:
Go to your Square Online Overview page.
Select Fulfillment > Shipping.
Confirm the Shipping from address. This address is used to determine the shipping rates and carriers (USPS, FedEx, etc.) available in your location. If you’re shipping from a different location, click Edit Address to make changes.
You should then be able to select flat rate from your options in the drop down menu - I cut and pasted from a Square article below:
Types of Shipping Rates
Which one should you choose? It depends on what you’re shipping. Here’s a quick overview of the options.
Note: Digital and Service type items do not count toward order price, weight, or quantity.
Calculates shipping based on weight and destination at checkout through carriers such as USPS, FedEx, etc.. This is a good option if you want to make sure your customers always get the most accurate shipping rates without being over or under-charged. For more details, check out our full article on Real Time Shipping.
Set a single price for shipping and charge either per order or per item. This is a good choice if you want to keep things simple and know that your shipping costs don’t vary much.
Offer free shipping based on order weight, order price, or for all orders. Use this in conjunction with other rates to give your customers a deal on larger purchases (for example, “Free shipping on all orders over $50!”).
Set your own rates based on the weight of all items in an order. This can work well when you ship within a limited area. This option will not take into account the distance to the destination or what carriers actually charge. You’ll need to make sure that you’ve specified a weight for each of your items.
Charge shipping based on the total price of an order. You could use this option to discount shipping for customers who spend more than a certain amount on a single order.
Charge shipping based on the number of items in an order. This is helpful if you’re selling items of a similar size and weight and your cost increases when you need to ship multiple items. This option will not take into account the distance to the destination or what carriers actually charge.
Create a Shipping Profile
A shipping profile is a combination of settings that control where and how you’ll ship your items. There are two types of shipping profiles: default and custom. The default shipping profile applies to all of your shippable items except those included in a custom profile. A custom shipping profile lets you set unique shipping rates and regions for specific items.
Note: You can set up multiple default shipping profiles as long as the location information such as states, prefectures, provinces, and countries are unique to each profile.
To set up a default shipping profile for all items:
Go to the Square Online Overview page and select Fulfillment > Shipping.
Click Set Up under 'Shipping Profiles'.
Enter a name for the new shipping profile. Your customers won't see this name.
Under Type, select Default.
Choose the countries you'll ship to in the 'Shipping To' menu. You'll be able to select specific states or provinces later. Note that you can't add a location to multiple default shipping profiles.
Click Add rate and choose an option from the dropdown menu.
Enter a name for this rate that your customers will see (e.g., Priority Mail).
Enter an amount to set the price for this rate.
Save when you're finished.
Alternatively, you can set up custom shipping profiles to charge custom rates, or create destination restrictions for certain items. Learn more about setting up item-level shipping rates
