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

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 It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired.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

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

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 ...

Contact your admin if you need help. Support options are available to admins who can sign in to the Microsoft 365 admin center with their admin account to contact support on behalf of users in their organization.

If you’ve already bought an Xbox gift card or code that doesn’t match your Microsoft account’s region, make sure to contact the retailer for additional support.

A phishing email is an email that appears legitimate but is actually an attempt to get your personal information or steal your money. Some deceptive emails appear to be from a safe sender but, in fact, have a "spoofed" source address to fool you. Here are some ways to deal with phishing and spoofing scams in Outlook.com. Spoof intelligence in Exchange Online Protection helps prevent phishing ...

Don't forget to include your license ID or agreement number, your contact phone number & email address so we can contact you. If you already have a volume licensing support case number, you may be in a location where you can phone the Volume Licensing support team.