By default Shipping Rate Add on requires Woocommerce add on plugin, to disable the Woocommerce integration is very simple just follow this steps. Note: This is only available form version 6.3.8 and up.

• Login to your admin dashboard
• Go to Sidebar menu WPCargo > Shipping Rate Settings
• Click/Tick the “Disable Woocommerce Integration?” checkbox field
• Click/Tick the “Save Settings” button