Creating Fields

Create fields in the checkout, registration of products and user registration!

characteristics:
creating field types
configuration affected areas eg checkout, registration of users registration products.
configuration editing these fields telling if a user can edit this field created.
reordering fields created or native at checkout and user enrollment
Hiding fields created or native.

and adding fields would be possible to add?

it is possible to create extensions for Eshop plus payment and Shipping?