Traditionally, marinating the meat is not a typical step in making a Philadelphia cheesesteak. The classic Philly cheesesteak recipe calls for thinly sliced ribeye steak that is cooked on a griddle or skillet along with onions and sometimes peppers. The meat is typically seasoned with salt, pepper, and other spices while it cooks, rather than being marinated beforehand.
However, variations of the cheesesteak recipe exist, and some people may choose to marinate the steak for added flavor. If you prefer a marinated version, you can marinate the sliced steak in a mixture of your choice, such as a combination of soy sauce, Worcestershire sauce, garlic, and spices, for a few hours or overnight before cooking. This can infuse the meat with additional flavors. Keep in mind that marinating the steak is not a traditional step in the authentic Philadelphia cheesesteak recipe, but it's a matter of personal preference.