Outlook: How to encrypt Email Attachments using 7-ZIP 1. Right Click document Find and right click the file you would like to encrypt. After right click find the " show more options " button and click it. 2. Add to archive More options should appear, find the 7-zip option. In the sub-section of 7-zip select add to archive. 3. Enter a password for encrypting Under the Encryption section, enter a password. This password will be used by the recipient to decrypt the file. 4. Click Ok Click "OK" to finish the encrypting process 5. Transfer file Finally we got our file encrypted, we can send this file as an attachment via outlook email. Make sure you send the file ending with .7z not the actual unencrypted .docs file. The recipient must also have 7-zip installed  to open the file and decrypt.