This post explains what is a Steam Friend Code and further explains how PC gamers can find and use Steam Friend Codes.

On Steam window, select the Friends tab on the upper left. Once you’re in the Friends window, click the Add a friend icon. Click on the COPY button to copy your own Friend Code.

Steam has a new program called Steam Families that makes it easy to share your entire game library with up to five friends or family members. We'll show you how to get set up.