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

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了解如何关闭双重验证。 双重验证是一项可选的安全功能，通过使用两种形式的身份，即密码和联系方式（也称为安全信息），这样别人更难进入您的 Microsoft 帐户。

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 It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired.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

A popular tactic of criminals is the "fake order" scam. The way it works is that you get a message, usually in email or text, that appears to be a routine confirmation for an order. Of course, you never ordered whatever product or service it's confirming. The message looks common enough, and it says that money will be charged to your credit card or withdrawn from your bank account for the ...

Learn how to use mobile operator billing as a payment option to buy Xbox subscriptions, games, and other content.

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 ...

在Outlook 中，可以为电子邮件创建一个或多个个性化签名。 签名可以包括文本、链接、图片和图像 (，例如手写签名或徽标) 。

Using Authenticator as a way to sign in If you have turned on passwordless, two-step, or multi-factor authentication for your account, use the following steps to sign-in: Go to the site where you want to sign in. Enter your username at the sign-in prompt and select Next. Select Send notification.

Learn how to fix error 807A1007 so you can join parties through Xbox One.