feat(user_manual): document system address book

Signed-off-by: Anna Larch <anna@nextcloud.com>

user_manual/groupware/contacts.rst

@@ -17,7 +17,8 @@ contact picture and manage your address books.
 Adding Contacts
 ---------------
 
-When you first access the Contacts app, an empty default address book becomes available:
+When you first access the Contacts app, the system address book containing all 
+users on the instance you are allowed to see, plus an empty default address book becomes available:
 
 .. figure:: ../images/contacts_empty.png
 
@@ -87,6 +88,9 @@ To edit or remove contact information:
 
 Changes or removals that you made to any contact information are implemented immediately.
 
+Not all contacts will be editable for you. The system address book does not allow you to modify 
+someone elses data, only your own. Your own data can also be modified in the :doc:`user settings <../userpreferences>`.
+
 
 Contact Picture
 ~~~~~~~~~~~~~~~

user_manual/userpreferences.rst

@@ -6,19 +6,15 @@ As a user, you can manage your personal settings.
 
 To access your personal settings:
 
-1. Click on your profile picture in the top, right corner of your Nextcloud instance.
-
-   The Personal Settings Menu opens:
+1. Click on your profile picture in the top right corner of your Nextcloud instance to open the menu
 
    .. figure:: images/oc_personal_settings_dropdown.png
       :alt: screenshot of user menu at top-right of Nextcloud Web GUI
 
-   *Personal Settings Menu*
-
-2. Choose *Settings* from the drop down menu:
+2. Clicking on *Settings* from the drop down menu opens the user preferences
 
    .. figure:: images/personal_settings.png
-      :alt: screenshot of user's Personal settings page
+      :alt: screenshot of users Personal settings page
 
 .. note:: If you are an administrator, you can also manage users and administer
    the server. These links do not appear to a non-administrator user.
@@ -47,3 +43,28 @@ include the following:
 .. note:: Available options and settings depending on your administrator's configuration.
    If you are not able to change the password or the display name in your personal settings,
    please contact your administrator for help.
+
+
+Sharing your data in the global address book
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Some administrators decide to share their global address book with other Nextcloud instances (so called *Trusted Servers*) or even with the wider world. 
+This is helpful when two instances want to work closely together, or when people want to use Nextcloud as a virtual telephone book for others to browse.
+It also allows searching for contacts, creating shares and much more.
+
+You can change what personal data of yours is shared by setting the scope of your data. Clicking on the lock icon will open the following dropdown
+next to each entry:
+
+   .. figure:: images/userdata-scope.png
+      :alt: screenshot of scope dropdown on personal information form field
+
+
+If you set your data to **Private**, nobody but you will be able to see it.
+
+If you set your data to **Local**, all logged in users within your Nextcloud instance will be able to see the information, but noone outside of it.
+
+If you set your data to **Federated**, the trusted server(s) which are added by your administrator will be able to see this data, in addition to all logged in users.
+
+If you set your data to **Global**, anyone can see your data. For some use cases this is wanted. 
+Someone with a public facing role such as marketing or sales might want to share their contact with a wide variety of connections which might not be using Nextcloud.
+