Learn how to install, use, and delete add-ins in Outlook for Microsoft 365, Outlook 2021, Outlook 2019, and Outlook on the web. Find out how to access add-ins from the store, custom files, or IT admin, and where to use them in messages, appointments, or meetings.

Learn what XLL files are and how to unblock them if you trust the source. Find out how to avoid malware and phishing attacks that use add-ins to distribute malicious code.

Add-ins provide optional commands and features for Microsoft Excel. By default, add-ins are not immediately available in Excel, so you must first install and (in some cases) activate these add-ins so that you can use them. Some add-ins are built in to Excel, such as Solver and the Analysis ToolPak.

Learn how to cast or mirror another device's screen to your Windows PC using Miracast. Follow the steps to install the Wireless Display app, connect to a wireless display, and add Cast to your quick settings.

Learn how to use Snipping Tool to take a snapshot of any part of your screen and make changes or notes. Find out the keyboard shortcuts, video snip options, and how to share your snips.

Learn how to download and install Microsoft 365 offline on a PC with a slow or unreliable internet connection. Follow the steps for your plan (Office for home or Office for business) and activate Office after installation.

You can now get Office Add-ins from the Store or use add-ins you already have from right within recent versions of Word for Mac and Excel for Mac. There are two kinds of add-ins: Office Add-ins from the Office Store (which use web technologies like HTML, CSS and JavaScript) and add-ins made by using Visual Basic for Applications (VBA).

Learn how to migrate your settings and add-ins from classic Outlook for Windows to the new Outlook for Windows during setup or later. See the list of imported settings, add-ins, and their web counterparts.

自动化加载项 可以通过“COM Add-Ins”对话框和“Add-Ins”对话框在 Excel 用户界面中加载 IDTExtensibility2。 下面介绍了自动化外接程序的行为，具体取决于它是加载在这两个对话框中的一个还是两个对话框中： 仅在“加载项”对话框中加载。 加载项按需加载。

Learn how to get and use add-ins in Outlook.com, programs or utilities that help you automate tasks in your inbox. Find answers to frequently asked questions, ratings, reviews, and support options for add-ins.