Learn how to install, reinstall, or activate Microsoft 365 or Office 2024 on a PC or Mac.

Depending on how you got your copy of Windows 10 or Windows 11, you'll need either a 25-character product key or a digital license to activate it. A digital license is a method of activation in Windows 10 and Windows 11 that doesn't require you to enter a product key.

Depending on how you got your copy of Windows 11, you'll need either a digital license or a 25-character product key to activate it. Without one of these, you won't be able to activate your device.

For more information, see Windows 11 specs, features, and computer requirements. To see if a Windows 10 device is eligible to upgrade to Windows 11, follow one of these options: Download and run the PC Health Check app. Select Start and then select Settings > Update & Security > Windows Update .

Find out how to manage your Xbox subscriptions to request a refund or cancel a recurring payment.

啟動 Office 立即開啟任何應用程式，如 Word 或 Excel，立即開始使用 Office 應用程式。 安裝後找不到 Office？ 大多數情況下， Office 會在您開始申請並選擇「 接受」後，透過同意授權條款後啟動。 Office 可能會自動啟用。

How to calculate the number of days, months, or years between two dates using the DATEIF function in Excel.

Project Online Professional or Project Online Premium: If you have a subscription to one of the cloud-based solutions of Project you won't see an option to install it unless you have an assigned license. If you're the Microsoft 365 admin responsible for assigning licenses, see Assign licenses to users.

Here are the most likely causes for an unrecognized charge: A Microsoft subscription has recurring billing enabled. Someone you know, such as a family member, bought something with your card. You can now investigate this on the Manage your payments page. A previously declined charge was charged again. A pre-order or split order was shipped. Someone made an in-app purchase from an app, game, or ...

Find solutions for Xbox account and profile issues, manage settings, and get support for your Xbox experience.