Certificate authority (CA) A certificate authority is an entity similar to a notary public. It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired. Top of Page Digital signature assurances The following terms and definitions show what assurances are provided by digital signatures. Authenticity The signer is ...

About digital signatures and certificates in Office, and buying a digital certificate from a certificate authority or create your own.

Learn how to record Teams meeting. Capture audio, video, screen sharing activity, and troubleshoot recordings in Microsoft Teams.

Audio issues on your PC can be incredibly frustrating, especially when you're trying to watch a video, attend a meeting, or listen to music. Fortunately, most sound problems can be fixed by following a series of troubleshooting steps. This article provides a comprehensive guide to resolving audio issues in Windows. The tips are listed in order, so start with the first one, see if that helps ...

Important: If you want to increase your chances of recovering a file, minimize or avoid using your computer. In the Windows file system, the space used by a deleted file is marked as free space, which means the file data can still exist and be recovered. But any use of your computer can create files, which may over-write this free space at any time.

Learn about the benefits of Microsoft 365 subscription - Microsoft 365 apps, extra cloud storage, advanced security, AI-powered features, and more.

Learn how to download files from the web, change your default download location, and find files you've downloaded on your PC using Internet Explorer.

Outlook 網頁版 是組織使用的網頁版 Outlook，您可以透過網頁瀏覽器存取與公司或學校帳戶相關聯的電子郵件、行事曆和聯繫人。 您的公司或學校帳戶通常會由組織中的人員指派給您。