Update 01-intro.md

Author: jasonjoh

tutorial/01-intro.md

@@ -9,6 +9,11 @@ This tutorial teaches you how to build a React single-page app that uses the Mic
 
 Before you start this tutorial, you should have [Node.js](https://nodejs.org) installed on your development machine. If you do not have Node.js, visit the previous link for download options.
 
+You should also have either a personal Microsoft account with a mailbox on Outlook.com, or a Microsoft work or school account. If you don't have a Microsoft account, there are a couple of options to get a free account:
+
+- You can [sign up for a new personal Microsoft account](https://signup.live.com/signup?wa=wsignin1.0&rpsnv=12&ct=1454618383&rver=6.4.6456.0&wp=MBI_SSL_SHARED&wreply=https://mail.live.com/default.aspx&id=64855&cbcxt=mai&bk=1454618383&uiflavor=web&uaid=b213a65b4fdc484382b6622b3ecaa547&mkt=E-US&lc=1033&lic=1).
+- You can [sign up for the Office 365 Developer Program](https://developer.microsoft.com/office/dev-program) to get a free Office 365 subscription.
+
 > [!NOTE]
 > This tutorial was written with Node version 12.16.1. The steps in this guide may work with other versions, but that has not been tested.