3rd Party Users with a PwC Email Address

We currently have contractors on our project with a PwC email address. We do not want them to have access to our SaveIT files which include our SOW.

In the future I would like to be able to add those team members as either: Client team members OR would like to restrict access to folders in the SharePoint. We currently do not have access to restrict folder access. If I have contractors in my SharePoint (they are automatically made team members with access to all files) I would like to restrict folder access.