You can either partner with print providers like Printful or Printify on your website, or ecommerce sites like Ebay and Etsy and start your own print-on-demand business or use platforms like Amazon, Redbubble, Zazzle and directly sell. Print-On-Demand needs some moderate skills such as:
Graphic designing: You need to design products
SEO: No matter what platform you are using, you still need to do SEO for internal and external ranking
Marketing: Without marketing, there will be no sales
