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 It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired.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.

Whether it’s a new job title (congratulations!) or a phone number change, make sure you keep your email message signature up-to-date. If you're using new Outlook, for more information about email signatures, or if you haven’t created one yet, see Add a signature to messages. Select File > Options > Mail > Signatures. Select the signature you want to edit, and then make your changes in the ...

Learn how to fix error 87E0000F so you can download games and apps on your Xbox console or Windows PC.

Open the app, go to the app's top-level menu, and then select Send feedback. After that, contact Support or go to the Microsoft Authenticator app forum and explain the problem you're seeing and the steps you tried.

When you try to create a new signature linked to your own account (cloud signatures), you notice that the newly created signature gets deleted after a while or you may find that the signature does not sync up with Outlook Web App (OWA).

In most cases, it’s best if the Microsoft Store and Xbox profiles are the same. When a mismatch is identified, the Xbox app will report it with a pop-up banner and a link to review possible changes. You’ll want to set your Microsoft account as the Store account for the best experience.

How to create or edit your Outlook signature for email messages. Include your signature, text, images, electronic business card, and logo.

Signing your email messages with a digital ID helps to prove your identity and prevent message tampering.

在Outlook中，你可以為電子郵件建立一個或多個個人化簽名。 你的簽名可以包含文字、連結、圖片和圖片 (，例如你的手寫簽名或標誌) 。