Hello!
I want to start using GSAP, I am a single developer and the only member of my team 
so what kind of license do I need?
When uploading the file to Envato do I need to add some special note that I use GSAP and that I have a paid commercial license?
Thank you!
You may use the code at no charge in commercial or non-commercial apps, web sites, games, components, and other software as long as end users are not charged a fee of any kind to use your product or gain access to any part of it. If your client pays you a one-time fee to create the site/product, that’s perfectly fine and qualifies under the “no charge” license. If end users are charged a usage/access/license fee, please sign up for a “Business Green” Club GreenSock membership which comes with a comprehensive commercial license
https://greensock.com/standard-license/
I don’t think you’d need to add any note but in case, you will be asked to provide one.