You can set a Password for a collection under Collection > Settings (second icon) > Password in your Dashboard. Only those with the Password will be able to view the collection. You can learn more about Passwords by watching our Password Video Tutorial here, or by scrolling to the bottom of this page!
Client Exclusive Access
Client-Exclusive access allows you to hide certain Sets of images from anyone logging in as a Guest while giving your client full access. You can learn more about Client Exclusive Access.