After you have accepted to work on a project and the project is completed and paid in full through GetAFreelancer.com, you will be able to do this by going to Provider Activity. You will find available service buyers to rate from there. Feedback can be left only when project is completed and paid in full (according to the provider's bid) via GAF. If the provider is paid less than his bid via GAF payment system, the feedback option won't be activated.