So I want to start me a t shirt clothing line but I want to print my designs on every part of my shirt in stead of just having one picture in the front for example. Also will I be able to buy white t shirts from Gildan or fruit of the look and resell them and what are the things I would need to sell and print my designs.
Yes you absolutely can buy and resell gildan and fruit of the loom shirts with your design.
For the type of printing you are talking about it is time consuming and expensive because of that. The process is called sublimation and there are companies that do it on demand but its pricey https://www.theprintful.com/custom/all-over-printing-sublimation
Thats why you usually see shirts with just one side printed… its a lot cheaper to make.