Designing temporary tattoos can be a very simple process if you keep a few design basics in mind. You can use paper and pencil to sketch out your design ideas, or you can use a computer and software like Adobe Photoshop or Illustrator. When you have a design in mind, you can use the tools in Illustrator to adjust the line weights and sizes of the lines.
Source: https://tattoosimplephoto.blogspot.com/2022/09/how-to-prepare-temporary-tattoo-simple.html