1. The value for the Shipping field will need to be mapped with a column that has the value of true/false.
2. If you are looking to make all your products shipping, then you can use the Update Product feed and input in the static value true. Please ensure you enable the option.
3. If you are looking to make all your product does not have shipping, then you can use the Update Product feed and input in the static value false. Please ensure you enable the option.