Need to use FeynArts to determine Feynman diagrams of a process with initial particles having no masses

Question

so i'm facing this problem in using FeynArts, i need to find the feynman diagrams of a process with intial particles not having masses, but i can't find the command to use to declare particles as being massless. Is there such a command for the FeynArts package, and if it exists could someone tell me how to use it ? .