In TALENT, this is called "Observer Sharing". Sharing a file with an Observer sends an invitation to view the file's page through their own private TALENT portal. Observers have view-only access to TALENT, so they won't be able to add comments to shared files, nor will they be able to upload their own artifacts.
Start by using the Share button on any of your TALENT files. When the sharing screen appears, click the green 'Share with Observers' tab on the right.
Enter the email address of the person you want to view your file. If you receive a message that they already exist in your system, click back to the "Share" tab, and try searching their name, or the beginning of their email address.
Finally, send the invitation by clicking the green Share & Notify button.