In the Friend section of the Configure Site > Social Networking page, you can choose to allow members to request/add other members as friends.  Like other features, you can choose/customize the respective buttons, and how to display them.  There are buttons to send a friend request, accept a friend request, and to friend/unfriend.

As a spamming control measure, here you can also set up the maximum speed of requesting friends/seconds.  If over the friend requesting speed limit, the member will receive the message to wait, the language which you can specify and customize here.

If you use the Friend feature, the respective friend button and member friends will display on the Public Profile page of a member automatically, if you are using the Default page type format, and the website visitor viewing the page is a logged in member, and not blocked by the member.  You can also choose to display the member's/logged in member's mutual friends and the member's friends recently added.  On the Configure Site > Social Networking page, just fill in the text for these fields to use, and you can also set how many days you count as "recent".

On their Edit Profile page, each member can view members they are friends with/have pending friend requests. and unfriend or remove the friend request, or add a friend to a friend group/create a new group if they would like on this page as well as the member's Public Profile page.  On the Edit Profile page members can also manage their friend groups, edit the group name/delete the group.

You can allow members to set post Privacy settings to share/not share with select friends/friend groups, on the Configure Site > Social Networking page, Privacy Settings section.  You can find more info on this on the User Manual topic "Customizing Privacy Options for User App Uploads".

Also, if you are using the Page Commenting & Rating feature, when a member posts a comment, the number of Friends they have will be listed under their username/profile picture.