更改桌面背景图像 - Microsoft 支持
在 “个性化设置背景”旁边的列表中，选择“图片”、“ 纯色”、“ 幻灯片放映”或“ Windows 聚焦 (”，) 查看来自世界各地的新图像。
Find the serial number on your Microsoft or Surface device
Learn how to find the serial number on your Surface so you can register your product or request service.
SUMIF function - Microsoft Support
How to use the SUMIF function in Excel to add the values in a range that meet criteria that you specify.
Applies To:
Excel for Microsoft 365, Excel for Microsoft 365 for Mac, Excel for the web, Excel 2021, Excel 2021 for Mac, Excel 2019, Excel 2019 for Mac, Excel 2016
Show or hide the ribbon in Office - Microsoft Support
Show the ribbon when hidden, and set options to shows tabs and commands, just tabs, or automatically hide the ribbon for the maximum document space.
Applies To:
Excel for Microsoft 365, Word for Microsoft 365, Outlook for Microsoft 365, PowerPoint for Microsoft 365, Excel 2021, Word 2021, Outlook 2021, PowerPoint 2021, Excel 2019, Word 2019, Outlook 2019, PowerPoint 2019, Excel 2016, Word 2016, Outlook 2016, PowerPoint 2016, Office 2016
Fix USB-C problems in Windows - Microsoft Support
Learn how to troubleshoot USB-C problems in Windows and fix USB devices, ports, and adapters not working properly.
SUMIFS function - Microsoft Support
How to use the SUMIFS function in Excel, one of Excel’s math and trig functions, to add arguments that meet multiple criteria.
Applies To:
Excel for Microsoft 365, Excel for Microsoft 365 for Mac, Excel for the web, Excel 2021, Excel 2021 for Mac, Excel 2019, Excel 2019 for Mac, Excel 2016, Excel Web App
Download free, pre-built templates - Microsoft Support
Find and download free templates to create documents like calendars, business cards, letters, greeting cards, brochures, newsletters, or resumes.
Applies To:
Excel for Microsoft 365, Word for Microsoft 365, PowerPoint for Microsoft 365, Access for Microsoft 365, Project Online Desktop Client, Publisher for Microsoft 365, Excel 2021, Word 2021, PowerPoint 2021, Access 2021, Project Professional 2021, Project Standard 2021, Publisher 2021, Excel 2019, Word 2019, PowerPoint 2019, Access 2019, Project Professional 2019, Project Standard 2019, Publisher 2019, Excel 2016, Word 2016, PowerPoint 2016, Access 2016, Project Professional 2016, Project Standard 2016, Publisher 2016, Visio Professional 2016, Visio 2010, InfoPath 2013
Add pictures or attach files to email messages in Outlook
It's easy to attach pictures, files, and other items to your Outlook messages. Outlook keeps track of the documents you’ve recently worked on, whether they're stored on your computer or saved in OneDrive (cloud only).
Applies To:
Outlook for Microsoft 365, Outlook 2021, Outlook 2019, Outlook 2016, Outlook on the web, Outlook.com, New Outlook for Windows
Windows 10 and Windows 11 in S mode FAQ - Microsoft Support
About Windows 11 in S mode. Windows 11 in S mode is a version of Windows 11 that's streamlined for security and performance, while providing a familiar Windows experience.
Change how the message list is displayed in Outlook
Choose how you want emails displayed in the message list, such as whether you want emails displayed as individual messages or as conversations.
Applies To:
Outlook for Microsoft 365, Outlook 2021, Outlook 2019, Outlook 2016, Office for business, Office 365 Small Business, Microsoft 365 admin, Outlook on the web, Outlook.com, New Outlook for Windows