Your shop offers free shipping however if customers want their orders to be shipped as insured then they will have to pay for insurance cost. Define 2 shipping methods via "Enter my own Shipping Charges" option

- Setup "Free Shipping" and "Insured" shipping methods methods.  During Checkout, a customer can choose 'Free Shipping' from the shipping methods dropdown and the shipping charge should automatically change to 0.00 amount. If they select the 2nd option (called "Insured") - then the shipping cost changes to something else -for example , US$ 15.00.

1. Select Central dropdown =>Shipping Charges

2. The shipping Charges window will appear

3. Select "Enter my own Shipping Charges" and click on the + button  to add another shipping method, call it Free Shipping -> click OK. This method will display, tick the box to enable it.

4. At the Setup Regions – “Free Shipping” window will display. Click on Local Region as well as Rest of the World and Click the Ok Button.

5. A prompt shows up: "Will this method be available for all Products?" Yes or NO -click Yes.

6. You will return to the Shipping Settings window, Click on the + to add another shipping method, call it “Insured” - click OK. This method will display, tick the box to enable it.

7. At the Setup Regions – “Insured” window will display. Click on Local Region as well as "Rest of the World" and Click the Ok Button.

8. A prompt appears: "Will this method be available for all Products?" Yes or NO-Click the Yes button.

9. You will return to the Shipping Settings window, so Click on the Next button.

10. Now you will get the Shipping Charges window

11. Click on Free Shipping => Local Region (in my example). Choose "By price" in Calculate Charges, and click on the + (add button) to add charges.

12. Enter 1,000,000 in the "To" range. This means from 0 - 1,000,000 price range. Shipping charge will be0.00(free shipping). Then Click Ok.

***Repeat steps 11 – 12 but this time selecting “Rest of the World”. 

13. Now, click on the “Insured” shipping method => Local Region. Choose "By price" in Calculate Charges, and click on the + (add button) to add charges.

14. Enter 1,000,000 in the "To" range. This means from 0 - 1,000,000 price range. Shipping charge will be15.00. Then Click Ok.

***Repeat steps 13 – 14 but this time selecting “Rest of the World”. 

15. Click FINISH.

16. Save and preview shop. Publish your shop so that the changes are uploaded online.