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

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 It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired.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

Xbox Support offers help for Xbox, Game Pass, and billing questions. Get advice and customer service in the Xbox Support community.

How to add a signature to your Word documents. You can also use the Signature Line command in Word to insert a line to show where to sign a document.

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

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 ...

Microsoft Authenticator helps you sign in to your accounts if you've forgotten your password, use two-step verification or multi-factor authentication, or have gone passwordless on your account.

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.

For technical support, go to Contact Microsoft Support, enter your problem and select Get Help. If you still need help, select Contact Support to be routed to the best support option.

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.