Learn how to manage your mailbox size and keep it within a specific size limitation with Microsoft Support.

Contact Microsoft Support. Find solutions to common problems, or get help from a support agent.

If you need to sum a column or row of numbers, let Excel do the math for you. Select a cell next to the numbers you want to sum, select AutoSum on the Home tab, press Enter, and you’re done. When you select AutoSum, Excel automatically enters a formula (that uses the SUM function) to sum the numbers. Here’s an example.

No matter where you live, work, or roam, there’s a version of Microsoft OneNote to fit your needs. Whether you’re on a PC, a Mac, in a browser, or on a mobile device, each version of OneNote lets you reliably access your cloud-connected notebooks to capture your thoughts and ideas.

Get Microsoft billing support. Find help with Microsoft Store purchases, subscriptions, refunds, payment options, and checking your order history.

See how Xbox cloud gaming works on Android, Apple, and Windows devices, as well as Xbox consoles and Samsung smart TVs.

Troubleshoot activation errors. If Microsoft 365 can't activate, it eventually becomes unlicensed and all editing features of Microsoft 365 are disabled.

Windows 10、Windows 11、Surface ドライバー、およびファームウェアの自動更新. 準備の手順に続いて、Windows 更新プログラム を参照して、更新プログラムを確認してインストールします。 または、下の [Windows の更新プログラムを確認する] ボタンを選択すると、Windows の更新プログラムを設定で開き ...

When you start a focus session, a focus timer will appear on screen. To use additional focus tools in the Clock app, expand the focus timer to get the full view of the Clock app.

Get help with signing in, changing passwords, creating and sending mail, deleting mail, creating folders, and more in Outlook on the web.