有一个共享链接选项，会出现一个弹出窗口，您可以给你的朋友用户名或他的电子邮件共享存储库。此弹出窗口显示类似于
的内容现有用户可以立即访问此存储库，新用户将收到邀请。

There is an option of share link, if you click on that, a popup will be appeared on that you can give your friends username or his email to share the repository. This popup says something like "Existing users are granted access to this repository immediately. New users will be sent an invitation."

UPDATE ：看起来接口略有改变。您可以通过设置/访问管理共享回购。

UPDATE: Looks like the interface is slightly changed. You can share a repo via Settings / Access management.