创建appxupload包时，它会要求您登录Microsoft帐户。 如果可能，您应该让您的朋友在您的计算机上，以便他们输入他们的凭据。

When you create an appxupload package, it will ask you to log into a Microsoft account.  If it's possible, you should have your friend at your computer so they can enter their credentials.

或者，您可以使用 Visual Studio Online ，它托管两种不同类型的源代码控制提供程序。 您要做的就是检查所有代码，授权您的朋友访问您的源代码控制，
并让您的朋友在您测试完所有内容后生成该软件包。 这实际上是首选解决方案 - 朋友可以下载VS 2015社区，连接到VS Online，下载代码并生成包。

Alternately, you could use Visual Studio Online, which hosts two different types of source control providers.  What you would do is check in all your code, grant your friend access to your source control, and have your friend generate the package after you've tested everything.  This is actually the preferred solution -- the friend can download VS 2015 Community, connect to VS Online, download the code, and generate the package.