One of the reasons why Malt was founded in the first place was to give freelancers a way to build their professional reputation.
Part of building that reputation involves receiving and publishing positive feedback from the clients they've worked with via Malt. This is why it's so important for you to leave the freelancers you've worked with a rating and a review at a project's completion. It is the key to helping them grow their presence on Malt and continue to land more projects.
Just remember that you have one month from a project's completion to leave and modify a review. After that point, no changes can be made.
And if you really want to make a freelancer's day, if you thought the work was done extremely well—or you simply appreciated the freelancer's continued collaboration—you are always welcome to offer the freelancer a bonus. To do this, please ask them to modify their quote before they mark it complete. Otherwise, once the project has been marked complete, no additional changes can be made to the quote. So, if you're feeling generous, don't want to tell the freelancer!