Yes you can, with Overleaf Pro.
An Overleaf Pro Account gives you 10GB of storage space, and lets you create unlimited password-protected documents. You control who has access, and can add & remove collaborators at any time.
Removing a collaborator revokes their access to the project, even if they still know the project link. You may add them again if you change your mind and wish to grant them access again in the future.
For more information and to upgrade, visit our plans and pricing page