With two-step verification, you'll get a security code to your email, phone, or authenticator app every time you sign in on a device that isn't trusted. Need more help?

A digital signature is an electronic, encrypted, stamp of authentication on digital information such as email messages, macros, or electronic documents. A signature confirms that the information originated from the signer and has not been altered.

If your passkey for a work account was created using a camera or authenticator app in your Personal profile, you will need to recreate a passkey in your Work profile.

Many apps allow you to authenticate by entering a code on another device such as a PC. If you want to sign in on a remote computer to install Authenticator, follow these steps.

No, Apple Watch and Android wearable devices (such as Samsung Galaxy Watch) are currently incompatible with Authenticator's security features, but you can mirror Authenticator notifications from your phone to your wearable device.

The Signature Details dialog box displays certificate information such as the signer’s name in the Signing as box, and who issued the certificate. Open the file that contains the certificate you want to view.

Learn how you can use the free Microsoft Authenticator app to sign in to all your accounts without using a password.

On the Tools menu, click Form Options. Under Category, click Digital Signatures, and then click Enable digital signatures for the entire form.

Learn how to use digital signatures and encryption in Outlook for Mac. Both the sender and recipient must have a mail application that supports the S/MIME standard.

We are working on an update to the Mac and iOS applications to support signing in by using an alternative user identifier. To resolve this issue, update to the latest version of Mac and iOS apps. Verify the configuration of AD FS 2012 R2 to let users sign in by using an alternative user identifier.