You upload your designs once and select products. If someone buys a t-shirt or other product from you, you get something for it. You don't have to send anything and get paid month by month into your account. Already the first year I made $500 with about 40 simple designs. Of these 40 designs about 10 were bestsellers. I will reveal the niche where I was able to sell my designs and give you tips on how you can earn more with your own products. I wish you good luck!
In the first months you will not make big money yet. But if you keep at it, you can make a good amount of money. The most important thing is that you don't give up just because you only make a few cents in the first few months and don't get paid out at all. It's the amount that counts, and you learn what works over time.
In the winter months you will probably make more. Especially during the Christmas season. So prepare yourself for this time. Upload as much as possible in September or October.
The platform on which I had great success is called Redbubble . It works like this:
Let's assume you are a hobby photographer and you are well versed in this field. So you design stickers or t-shirts for photographers. If you design products with a text that people search on Google, your products will be indexed on Google. For example a quote from a famous photographer or a famous photographer joke.
Think first about the products a buyer wants. Does a photographer put stickers on his sun visor? If so, what would be something he would like to have there? A drawn Nikon logo for example?