The answer to this question depends on the decisions you make during the implementation process. The basic choice is
Do you want to allow anonymous users (i.e., guest users) to make purchases, realizing that these will provide billing and contact information when they check out?
Would you rather require users to be registered, meaning they have to log in to your portal before they can buy?
Again, the decision is up to you. Either option is available and can be decided during your implementation phase.
However, let's assume for the moment that you choose option A.
If you recall, we touched on the GUEST user scenario in Section 7, “Creating the Guest Customer”. In that section, we described the ERP setup required to prepare for just this use case. Anonymous users assume the role of the GUEST user. With the GUEST user's privileges, anonymous users can browse your online catalog, add items to their cart, and then check out with the pre-defined payment method(s).
Of course, while these users are paying for their purchase, you will be collecting billing and shipping contact information from them. All of this important contact information will be stored in the CRM module of the ERP. However, from the anonymous user's perspective, they will have done all this without actually registering as a user on your portal.