The functions available to a person with whom you share a PayBook depend on the mode in which you shared it.
There’s visitor mode, in which the user can see the PayBook and its content but not modify it. There’s also user mode, in which the user can make changes to the content.
Within user mode, when you collaborate on a shared PayBook, it’s possible to add transactions to that PayBook, even if you didn’t create it and it’s only available on the “Sharing” tab in your Glass account.
You may also add labels to the transactions of other users with access to that PayBook