Compose an E-Mail in the E-mail app as usual.

In the Compose new E-Mail page, click the Encrypt icon on the top right side.

You can also click on Security options on the left. Activate Enable Guard.

To further increase the security level, you can use further functions: set an expiry date or time, use an additional password

Click on Send secure.

When sending to external recipients, a window is displayed that allowssending notes for opening the encrypted E-Mail to the external recipients.

In the Compose new E-Mail page, click on Security options on the left side.

To further protect the E-Mail encryption with an additional password, enable Require Additional Password. The Extra Password window opens.

Enter the additional password in the fields Password and Confirm. Click on OK.

To set an expiry date for the visibility of a encrypted E-Mail, select an entry from Retract in.

Open the Sent objects folder. Select an encrypted E-Mail that you sent.

If being prompted for, enter the Guard security password.

You can define how long the security password should be remembered. To do so, enable Keep me logged into Guard. Select a value from the list.

The sender might have protected the E-Mail with an additional password. In this case, an additional input field will be displayed. Enter the additional password in this input field.

Click the More icon in the detail view. Click the Retract menu item. The E-Mail can no longer be read by the recipients.