Note: This article applies only to Office 365 operated by 21Vianet in China.

As an admin who has signed up for Office 365, there are a few important setup tasks to do before the people in your organization can use Microsoft 365.

Add your users and domain

You may want your email addresses to use the name of your organization like or These are examples of custom domains. Many organizations want a custom domain. If you don't want to add a custom domain, you can continue to use the domain you created when you signed up for Microsoft 365; for example,

To add a custom domain, you need to have a registered domain name. If you don’t already own one, learn how to buy a domain name.

Once you have a registered domain name, you are ready to set it up. You can do that by stepping through the setup wizard. See Add a domain to Office 365.

If you just want to download and use Microsoft 365 apps, like Outlook or Word, you don't need to add a custom domain. Simply Install Office with Office 365 operated by 21Vianet.

Install Office applications

When you use Office with Office 365, you can edit and review Office files from virtually anywhere you can use your computer or web browser. It can be installed on the same computer that has an earlier version of Office. Depending on your operating system, here’s what Office includes:

  • Office on your PC includes Access, Excel, Lync, OneNote, Outlook, PowerPoint, Publisher, and Word.

  • Office on your Mac includes Excel, Outlook, PowerPoint, and Word.

  • Microsoft 365 Apps for enterprise includes Word, PowerPoint, Excel, Outlook, OneNote, Access, Publisher, and Lync.

To learn how to install Office, see Install Office with Office 365 operated by 21Vianet .

Set up SharePoint Online and Skype for Business

SharePoint Online includes team sites. One SharePoint Online site has already been created for your organization, and you can create additional sites as needed for specific teams and projects. A team site provides a central place to access your organization’s documents and business information from almost anywhere.

You’ll need to give people permission to access team sites. Once you set up the sites and assign owners, each team site owner can customize their sites with shared lists, calendars, pages, a site mailbox for storing team or project email, and more.

In addition to team sites for groups and projects, each person in your organization can use OneDrive for work or school to upload documents. They can then access these documents with a variety of devices, even when they’re away from the office. To get to the SharePoint Admin Center, do this:

  • Go to the Microsoft 365 admin center. To get there, select the app launcher icon App launcher button in the upper left and choose the Admin tile.

    Once in the Microsoft 365 admin center, expand Admin or Admin centers, and then choose SharePoint.

With Skype for Business, you can have online meetings, see if your coworkers are online, communicate with them through instant messaging (IM), audio calls, or video calls. You can even conduct online presentations that include audio, video, screen-sharing, and a virtual whiteboard. See Set up Skype for Business.

Inform your users

Your users are now ready to sign in and start sending and receiving email, accessing team sites, and collaborating online.

  1. Tell your organization what to expect. Send an email message to the people in your organization, telling them that they will soon be using Microsoft 365.

  2. Send instructions to each user. All users should have a user ID and temporary password, which were sent to them by Microsoft 365 when you created their user accounts. When you’re ready to roll out Office 365, send each person an email message that contains the information they need to get started:

    • The URL to access the Office 365 portal page:

    • A link to Get started with Office 365 which includes instructions for the common tasks that users need to do first.

    • Information about who to contact for help (probably you).

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