Self-employed third party documentation

[Stf maple leaf]

Hi guys, I'm new to this community. I work as self-employed painter and I actually very little have about a third party documentation by which I add value to my immigration file, so plz i need your help to show me how it should be and whether or not i should include the price i charged my clients with, and also should it indicate whether I worked as a full time or part time?

If you feel you can help plz don't hesitate.

Thanks in advance