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

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

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 It issues digital certificates, signs certificates to verify their validity and tracks which certificates have been revoked or have expired.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

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 ...

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.

Microsoft 365 troubleshooters Get Help has troubleshooters for Microsoft 365 you can run for many common scenarios. These often help resolve issues without the need to contact support. If a troubleshooter is available for your issue, select Start to run that troubleshooter. Available Microsoft 365 troubleshooters

Learn how to activate Windows using a product key or digital license, check your activation status, and link your Microsoft account.

Send S/MIME or Microsoft Purview encrypted emails in Outlook using a work or school account with a qualified Microsoft 365 subscription.

You can apply sensitivity labels to your files and emails to keep them compliant with your organization's information protection policies. Sensitivity labels are configured by your administrator and because they're published to users rather than locations such as sites and mailboxes, users in the same organization might see different sensitivity labels to apply. Sensitivity labels help ...

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.