I would like to change message
"Sorry, no quotes are available for this order at this time"
In which file, i can change? Can it will be manageable by Admin?
There is a simpler way of changing that text.
Copy this file: vendor/magento/module-checkout/view/frontend/web/template/shipping.html
to your custom theme at this path: app/design/frontend/YOUR-VENDOR-NAME/YOUR-THEME-NAME/Magento_Checkout/web/template/shipping.html
Change the text in line 82, which will begin with: translate=" 'Sorry....
You can change the text between the single quotation marks to whatever you would like to display on the frontend.