In Iris, you have the option to invite a friend through a special link.
When they download and install Iris using your link you both get 1 month free usage of Iris.
The best thing is that the effect stacks, so if you invite 2 friends, you will get + 2 months
To do this, first, make sure you have Iris installed
Then, just click on the Invite Friends button in the menu
When you do that, you will get to this screen
Now you can share this link with your friends and they can download using it
When they download and set up click this: