How does multifactor authentication work? Let's say you're going to sign into your Microsoft account or work or school account, and you enter your username and password.If that's all you need then anybody who knows your username and password can sign in as you from anywhere in the world!

Microsoft account help and support. Get help with signing in, locked or compromised accounts, linked accounts, closing, reopening, and updating your security info and account profile.

一次性购买 （示例：Office 小型企业版 2021）. Microsoft 365 订阅 (示例： Microsoft 365 家庭版 或Microsoft 365 个人版) 成本. 支付一次性成本。 每月支付少额费用，或支付年费以节约成本。

Import a text file by opening it in Excel. You can open a text file that you created in another program as an Excel workbook by using the Open command. Opening a text file in Excel does not change the format of the file — you can see this in the Excel title bar, where the name of the file retains the text file name extension (for example, .txt or .csv).

如果知道用户名和密码但已停止工作，请阅读 我的用户名和密码已停止工作。. 如果你忘记了 Microsoft 帐户用户名或电子邮件地址， 并且 之前已在 Microsoft 帐户上设置了其他 安全信息 ，请按照以下步骤操作。

提示: 若要编辑或删除来自于阻止发件人或安全发件人列表中电子邮件地址或域的电子邮件，请在列表中选择项目，然后选择 或 。. 若要清空垃圾邮件文件夹，请在左窗格中选择垃圾电子邮件。在屏幕的顶部，选择全部删除。

借记卡上的资金不足; 信用卡已到期; 你的信用卡被盗，因此你关闭了该帐户; 你收到了一张新信用卡，并关闭了旧信用卡

A message that is encrypted by Microsoft 365 Message Encryption is delivered to a recipient’s inbox just like any other email message. If the recipient has Outlook 2016 and a Microsoft 365 email account, they'll see an alert about the item's restricted permissions in the Reading pane.

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Warning When removing an email alias that’s connected to a Microsoft domain (such as @Outlook.com, @Live.com, or @Hotmail.com), that email is completely deleted from our systems and can’t be used to send or receive emails. It won’t be available for use again as an alias on another account. Microsoft doesn’t recycle email addresses, so it can’t be reclaimed at a future time.