you draw a bunch of designs, by hand then on pc, or on Photoshop, Illustrator (better because it doesn’t care about resolution) etc. then you do all the Arizona Wildcats NCAA Men’s Basketball Tournament March Madness 2023 Shirt besides I will buy this colour variations of the designs. then you choose the best one and keep a few colour variations of that one. then you go to a printing club, shop or online service, provide the image at the best resolution possible (unless you did everything by hand) and they pick it, print it on special paper, or make a multi-layer stencil for serigraphy, or use sublimation and print your design. the company might also produce t-shirts, so if you plan on selling them it’s best to look for companies which treat their workers with respect and pay them the right amount of money when making the t-shirts your design will be printed on. also, if it’s environmental-friendly cotton it’s better, since many people foster this mindset of sustainability and every label must become sustainable by 2020. then you need a shop, either physical or online, a bank account or Paypal, and some free time to do the shipping. also, get a lawyer and a business consultant.