Embossing on a cloth (polyester) napkin? You betcha! I embossed the leaves first on PRINTER PAPER...do not use cardstock for this project. Cut out your leaves. Then treat them like decals and iron them onto your fabric. I had my iron set on the medium heat, and I just pressed it for about 20 seconds. No steam, and no back and forth with the iron.
You need colored embossing powders for this project.
Other: Tangerine Tango, Gumball Green, and Early Espresso embossing powders, cloth napkins, iron.