Set Manually (per order) or as Default
Extra Cover/Insurance can be applied per order if not commonly required on your store. Otherwise it can be set as default to apply to all orders.
Each Carrier will have it's own insurance or transit cover options.
Set Default Insurance settings
To set a default settings that is applied to all orders, edit the chose Carrier settings, by going to Carriers > Edit Carrier, as shown:
Then in the default options, you can modify insurance settings.
In the case of MyPost Business, your options are shown here:
Change Individual Order Insurance Settings
You can also edit each orders settings, before generating a label.
This is done using the 'Order Options' section in the order, which may need to be expanded, depending on how you have configured the display of your orders in the app's order grid.
Edit the relevant setting, and this will refresh the rate quote automatically.