From your Shopify admin, go to Online Store > Themes.
Find the theme that you want to edit and click Customize.
In the left-hand toolbar, click Theme settings.
Click Shipping rates calculator.
Show the shipping calculator: set Yes to display the shipping rates calculator on your cart page, or No to hide it.
Heading text: enter the text that will be displayed above your shipping rates calculator.
Default country selection: choose which country will be selected by default.
Submit button label: enter the text that will be shown on the submit button.
Submit button label when calculating: enter the text that will be shown when the shipping price is being calculated.
General: enter the messages you want to show in error messages. Note: Use the "messages" variable to display dynamic messages.
Country is not supported: enter the message you want to show if your customers' country is not supported.