There are many types of marking machines, but very few are to type directly on plexiglass. The reason is that the organic glass itself is the transparent material, its energy penetration rate is high. There are several ways to type successfully on plexiglass.
Apply the paint that is easy to scrub in the position where is need to be marked, for example, the advertising color of gouache pigment, which is cheap and easy to clean (be careful not to smear too thick). Take advantage of paint absorption energy to achieve the goal of marking. After finishing, the wet towel can clean it up.
Generally, plexiglass has protective film, you can use the larger energy to mark the protective film and then tear it off when finishing(it is not suitable for every material).
Penetrate. This is pressing the side of the plexiglass which is needed to be marked on a plate with a high laser absorption rate, and then marking through plexiglass downward, which using the reflected heat to produce imprinting(this method is not recommended, because it is troublesome, and the success rate is very low).