You can use latex paint and fabric medium to paint a fabric chair. Here's one from another Hometalk member that includes the exact recipe for the paint in the tutorial. I hope this helps you. Wishing you the best.
I know it's a thing that people do but one that I had the opportunity to sit on was quite stiff and did not feel good. That being said it probably makes a difference on type of paint. https://www.hometalk.com/search/posts?filter=painted%20chair%20fabric
Hi Pat! Make sure you have a spray bottle with a bit of water in it and that your paint is slightly watered down. This will help the paint have a smooth finish and soak into the fabric. Have fun!
You can paint fabric with watered down paint.
You can use a brand called Deb's DIY Paint, she painted an entire velvet sofa with it, here's her tutorial https://debisdesigndiary.com/how-to-paint-upholstery-keep-the-soft-texture-of-the-fabric-even-velvet/