Ask Grapeviners did not work for me

Hi Guys, I posted the same query (link attached too) on Ask Grapeviners, but it didn't receive any attention. Hence, I am posting it on the Software Engineers’ Community, hoping to get at least a few inputs. Have a nice day and thank you for reading.

I have been working with a client from abroad for around a year, during which I built new applications and contributed to their existing projects, also assisting them with short technical tasks. I received payments on a project/milestone basis; should I formalise this as a contract and list it as a contract experience? The client is happy to do it since I have helped them in some crucial situations.

Please guide me on what documents I require to show as experience, and how I should formalise it, since all the work I did was handshake deals.

https://www.grapevine.in/post/Should-I-get-retroactive-effective-contract-from-client-a03e250a-ddd8-4b39-8971-1c321347d5e0