Org Friends are a collection of people who’ve been added to your Blissbook account, who are not Members of your organization. Members of your organization in Blissbook are typically your employees, so Org Friends are typically not employees.
The most common way someone ends up on your Org Friends list is because they've been directly added to the audience of one of your documents and they are not a Member of your organization. Directions for how to add someone to a document's audience are in this help article.
The Org Friends Tab/List
The main use case for the Org Friends tab, and adding someone as a Friend while on that tab (the "Add Org Friend" button), is if you want to add or remove people (who are not Members) to or from multiple documents at the same time.
For example, if you have 10 live documents and a person has been added directly to the audience for 8 of them, it is easier/faster to go to the Org Friends tab and archive them there instead of opening 8 different audiences and revoking access on each one.
Note: If you're (A) granting access to one or just a few non-Members or (B) only have one live document, you should instead add people individually and directly to the audience of your document(s).
Example Use Case
I have 2 live documents, my Employee Handbook and Code of Conduct. They're shared with "Everyone at ACME Inc", which is all the active people on my Org Members tab.
For whatever reason, there is a separate group of people who do not get synced over as Org Members (maybe they're contractors?) who need access to both of these documents.
Rather than including them in my Org Members list, I will create a group called Contractors, and add that group to the audience of both of these documents.
Whenever I have a new person who needs access to these documents, I go to my Org Friends tab, click the Add Org Friend button, and put them in the Contractors group when I add them. Because the Contractors group is in the audience of both my Employee Handbook and Code of Conduct, the person will gain access to both documents at the same time.
Adding someone directly as an Org Friend on the org friends tab doesn't do anything in itself. It only does something if you assign the person you're adding to a group that has access to something.
For example, if you have a document shared with your EMEA group, and you add someone as an org friend and place them in the EMEA group, then that person will be gaining access to that document.
If you add a person on your Org Friends page and don't put them in a group, or you do put them in a group but that group isn't in any audiences, then you aren't actually doing anything other than creating a user record.
Any time you add an Org Friend directly (on the Org Friends tab), add a non-Member directly to a document's audience, or add a non-Member as a Teammate/Collaborator, you are adding that person to your account manually. There are no automated email notifications for Org Friends.
If and only if the person you add is gaining access to something, Blissbook will prompt you to ask whether or not you'd like to send a notification. Not getting a prompt? This means that whoever you are adding isn't gaining access to anything. This is likely because either the document they're being added to is not live (i.e. it's still in draft) or they are being added to a group that does not have access to any documents.