From PackRat Recipe Wiki

Your pack link distinguishes you from other PackRatters. Essentially it's the URL that other people use to access your pack.

There are two methods to retrieving your pack link.

The first and arguably the most reliable method is to go to your Leaderboard and click your name. Your name is always highlighted with a shade of light blue.

The second and faster method is to find the word "you" in your history and click it.

In both methods the address located in your address bar is your pack link.