Thanks for reaching out to us!
To change eye color on our web editor, upload your image and head to the Retouch tab (on the left bar), choose the Eye Color tool and paint over the eyes on your image. Note that a Premium membership is required to apply this tool.
A similar tool exists in our iOS app and can be applied for free (by starting a free trial or by watching a reward video). Our Android app is coming soon.
Let us know if you have any other questions!
Regards – The Ribbet Team