It's easier to draw on paper than on fabric.
With these markers, you can draw on regular paper, then place the drawn side down on the fabric and iron it, and the color will transfer. Remember that the design will be a mirror image of what you draw.
There are many exciting ways these markers can be used.
On natural materials, the transfer is temporary; on polyester, it becomes permanent.
The iron temperature must be at least 180 degrees Celsius.
This means you can use it to decorate and upgrade polyester clothes with your own drawings (and you can draw over things you print out or copy, etc.) but you can also use it as a temporary way to mark embroidery or sashiko patterns!
What you have drawn can be transferred more than once, so if, for example, you are going to sew the same pattern or motif more than once, you can draw it once and then iron it over where you need to embroider multiple times. Incredibly practical.
See more about how I tested it on the product page for the 24 and 36 packs.
A personal recommendation after some testing is to first transfer to a test swatch with slightly lower heat and for a shorter time to remove "excess" color from the drawing, and then increase the heat and iron longer to get a nice design on what you want it on.
NB! POLYESTER MELTS! For example, place a thin cotton fabric between the iron and the paper and the fabric/garment, to avoid melting the fabric. This also protects the iron from color.
On textiles with a blend of natural fibers and polyester, the color will be weaker than on pure polyester. You can also combine drawing and embroidery. For example, color a motif and embroider some details or outlines.