Change from a 32-bit version to a 64-bit version or vice versa. Activate Windows. Fix Bluetooth problems in Windows. Learn how to install, reinstall, or activate Microsoft 365 or Office 2019 on a PC or Mac.

Download and install or reinstall Office 2019, Office 2016, or Office 2013. Office 2019 Office 2016 Office 2016 for Mac Office 2013. If this is the first time you're installing Microsoft 365 you may have some setup steps to do first. Expand the learn more section below.

When you enable an add-in, it adds custom commands and new features to Microsoft 365 programs that help increase your productivity. Because add-ins can be used by attackers to do harm to your computer, you can use add-in security settings to help protect yourself.

There are different ways to remove apps and programs, so if you can't find the one you're looking for, you can try another location. Note that some apps and programs are built into Windows and can't be uninstalled. You can try to repair a program first, if it's just not running correctly.

Use the Office offline installer to install Office 2016 or Office 2013 if you don't have an active Internet connection or you're having problems with slow speed or unreliable connections.

Sign in to SharePoint. SharePoint is a browser-based app that you connect to through your web browser, like so: Go to office.com, and sign in to your work or school account. In the upper left corner of the window, select the app launcher > All apps > SharePoint.

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.

When you select the Import Settings option during setup, the web add-in counterparts of your existing COM add-ins in classic Outlook for Windows are installed in the new client. The following table lists the applicable COM add-ins and their web add-in counterparts.

Use an add-in while composing a message. Create a new message or reply to an existing one. From the ribbon, select the Message tab, then choose the add-in you want to use. If the add-in doesn’t appear in the ribbon, select Apps to view your installed add-ins.

Add-ins in Outlook.com are programs or utilities that help you automate tasks when you view or create messages. Microsoft has partnered with leading companies to build add-ins that help you get things done right from your inbox.