Edit the text for shipping option

I’m trying to edit the text for the shipping option under View Cart and Checkout.
Both instances are actually the same, orders that don’t have a shipping option. However for the same instance, the View Cart and Checkout options show different text to the customer.

1st, under the View Cart, it shows: “Please use the shipping calculator to see available shipping methods.” – this is after I’ve used the shipping calculator. It won’t show any option as I’ve set up the shipping to certain locations to have minimum orders.

2nd, under the Checkout, it shows: “There doesn‘t seem to be any available shipping methods. Please double check your address, or contact us if you need any help.” under the Shipping and Handling portion.

I wanted to edit the text to display (on both View Cart and Checkout opions): “Your location requires a minimum purchase of “X amount” to continue with our checkout process. Please contact us if you need any help.”

Please let me know where I can find the php file to edit, and which lines. Thank you.