The Collection Password allows you to add a password to the full collection. To gain access to the collection, the password will need to be entered correctly before you're able to view and access the images.
Your Collections are accessible from your Client Access Portal, on your Pixieset Homepage. You are able to choose which Collections are displayed and accessible from your Homepage by adjusting the Homepage Visibility, to either "hide" or "show" the collection. In addition to hiding a Collection, you can also password protect your Homepage for extra security, read more about doing this here.
Client Exclusive Access allows you to create two unique logins, one for your Client, and one for their Guests. The Client Login, allows you to add special permissions to the images, such as allowing you to set certain Collections to be hidden to your clients only, as well as even allowing your clients to mark some images private from their guests, that may be more personal.
Check out this helpful video tutorial going over Password and Privacy options; how to set them up; as well as see what the client will experience on their end.