Hi Sarah,
Thanks and welcome to Adobe Community.
Yes you are right, in order to send out the file for the review for the reviewers to add comments, you can choose the option send for shared review. Once you have added the comments to the CREV file, you can save them through the save option in reviewer and then send the CREV file through an email as well.
PS: Please make sure you run Captivate Reviewer as administrator, else you won't be able to see the login option.
Thanks!
