We suggest you set up roles in pair like the example below (read more here):
- B2B (with e.g. customer user rights)
- B2B Pending (this role has no rights) or call it anything else e.g. Request B2B role
So now you have two roles, the later is to use in your registration form (selected in settings).
After a user has submitted the form, the user will be created in WP admin. To approve the user – go to Users > Request B2B (role). Here you find all customers not approved (no user rights), then check the ones you want to approve + Change role to… (dropdown) and select e.g. B2B (the role with customer rights) + click the Change button. That’s it.