I couldn't figure out how to get a good copy in here but you should see this on your home page of ISS - your assigned shops, web and phone shops, etc. Look above this to find Refer Friends, ISS Prep, Ticket System and Secret Shop Forum and Logout.
The circles should be horizontal but they changed to vertical when posted.
When you login to iSS and on the main webpage, LOOK AT THE TOP, and you will see the following list:
Refer Friends iSS Prep Certifications Ticket System Secret Shop Forum English (with an arrow) Logout
It is on the same line as the LOGOUT but in the opposite corner.
I tried to upload a screenshot, but the system would not paste it, so here is the manual information. Hope this helps all!
REMEMBER: look in the upper left-hand corner of the top of the page, that's where you'll find the Refer Friends choice.
As Wendy said - you can find the referral section at the top of the homepage of iSecretShop.com. When you click it, it will give you 3 different ways to send the referral link - including directly copying it from there and sending to anyone you wish, via any method of your choosing.