I bought a large assortment of Sharpies in all colors, wasted money. They bleed, run, and still leave partial images. I find them permanent only where I don't want them.
I like the Crayola for Fabric pens and always heat set after writing. Be aware that the Crayola pens that say Washable are the ones that wash out and are often used for markings that you want to get rid of after completion of the project. Tulip also makes fabric pens. Whichever line you choose, a piece of freezer paper with shiny side ironed onto the wrong side of fabric will make it easier to write, then peel off the freezer paper and re-use.