From the Overview page, select Office apps and on that page, find the Microsoft 365 product you want to install and select Install. To install Microsoft 365 in a different language, or to install the 64-bit version, use the dropdown to find more options.

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. Tip: If you don't see the SharePoint app under All apps, use the Search box near the top of the window to search for SharePoint.

Select File > Get Add-ins. Alternatively, in Word, Excel and PowerPoint you can view your add-ins by selecting Home > Add-ins.

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.

Change or reset your PIN. A PIN is a user-defined set of numbers, or a combination of numbers and letters, that allows you to sign in to your Windows device instead of a password. Your PIN is securely stored on your device, it isn’t transmitted anywhere, and it isn’t stored on a server.

Excel is blocking untrusted XLL add-ins by default. Add-ins can add a lot of functionality to Microsoft 365, but they are often used by people with bad intentions to distribute malware to unsuspecting victims. Add-ins aren't required for everyday use like reading or editing Excel workbooks.

Click File > Get Add-ins. Alternatively, you can click Home > Add-ins. You can directly install add-ins from this page or select More Add-ins to explore. In the Office Add-ins box, click Store tab. Browse for the add-in you want.

If an Office add-in isn’t showing up in the Office Add-ins list, refresh the list to see all of your add-ins. In Word 2016, Excel 2016, or PowerPoint 2016, click Insert > My Add-ins. In Project 2016, click Project > My Add-ins. Then click Refresh to update the list in the Office Add-ins dialog.

For guidance on how to locate the Apps button to access add-ins while reading or composing a mail item, see Use an add-in in Outlook. In the Apps page, search for the add-in you want from the available list. Alternatively, if you're after a specific add-in, enter its name in the search box.

COM Add-ins present the developer with a way to extend the functionality of Office applications for custom tasks. COM Add-ins are typically used to automate Excel in response to a click of a CommandBar button, a form or dialog box, or some other event specific to Excel such as opening or closing workbooks or entering data on worksheets.