what is the different document said "Full Access users." and "Host Company Full Access users."

Summary:

we see this in the user detail

This permission is only available to Full Access users.

Web Services Only Web Services Only users are special user accounts which do not have access to the CPQ user interface., they can only log in via API. They are intended to be used as part of an integration, automation or other remote access scenario. Web Services Only users are not counted against the site's quota of user licenses, but they will consume API interactions when used.

This permission is available to Host Company Full Access, Sales Agent, Channel Agent and Restricted Access users. It is not valid for guest or superuser accounts.