This is a tutorial on how to “draw” a satin (material) surface, I dont know what you would want to use the satin drawing for, maybe for a header image or blend background, maybe for digital paintings that have satin clothes etc. Either way, this is something I do in Photoshop when I am bored.

First we start off with a blank document, which we fill in with black (or any darker colour). I like to start off with black, that way you can colourise it later on, because some colours (like red) as a starting base can get bad highlight colours that look wrong.

Now we use the dodge tool on a soft brush (size 100) set on shadow, and dodge spots into the black.

Next we change the dodgle tool to highlights and dodge the center of the white spots to make it appear whiter, the more white, the shinier the satin will be.

Now we get the smudge tool and set it at 80%. I use a big soft brush set at around 100. Smudge areas in an up and down motion, each smudge stroke is an individual smudge, not all a continous line, and not reaching the bottom of the page.

Don’t make all the strokes meet in the middle either, make it randomly spaced and wiggle the brush every now and then to create more shape.

Get the burn tool and burn the black/grey ares to a darker shade, so the highlights stand out more.

Now do the same with the dodge tool on the highlights to make them brighter. The brighter you go the shinier the satin appears

Now you can colorise the image (go to Image>Adjustments>Hue/Saturation and click on colourise) Change the colour to whatever you want.

Now you can leave it there and it’s finished, or you can add a pattern to it. Choose a pattern you like and make a new layer above the satin. Fill the pattern

Set the pattern layer to multiply. You can change the opacity of the pattern layer as you desire to make it blend in more.

You don’t have to use just patterns, you can use brushes, rainbow gradients, and more. Experiment with different size smudge tools, and see what you come up with.
Here is one I made, looking like water.