This article explains how to add people to your friend list by scanning their Snapcodes.
Your unit might make a shutter sound and the screen may flash, signaling the screenshot was taken successfully.
Here’s how to find and share your code.

Tap yourprofileicon in the upper-left corner of the screen.
You should see your Snapcode here along with other profile information.
Select it to open it up and make it larger.

Your friend can then take a snap of your code to add you to their Snapchat friend list.
Here’s how to make one.
(Or don’t.
It works fine with an off-center face too.)
Choose the one you like best and selectContinue.