The order from items were carefully added because some Payment Gateways require certain infos to be able to transact successfully. However, if you want to go ahead and are aware of the problems that might arise in doing this, removing details in the order form can be done just follow the instructions below:
1. The file is found in this path packages/jb_ecommerce_express/blocks/jb_ecommerce_express/view.php
2. At lines 452 to 693 are the form details. You can remove the info or comment them which is safer.
Again, we discourage doing this but if you want to go ahead and just fine tune the info from the form just make sure to check the your cart still checks out without problem. If all else fails, we do offer paid customisations, just let us know.