Use a hair dryer and vinyl sticker sheets ( cricut sells perfect ones) that you can cut out on the forge. The hair dryer will take care of any wrinkles.
Also pro tip when doing stencils, paint over the stencil with the base color first, let dry, Then paint the color you want the letters to be. you will not have any runs if you do it this way. I know in your case its glass and only one color.
vinyl stickers are not laser-safe. They are PVC-based and when lasered they release fumes that are harmful to you and to your machine. Polyester decal material can be substituted for vinyl in many cases, and is laser-safe.