Theres alot of historical evidence of Muhammad and his contact with Romans, Persians and Ethiopians so he was most probably a real person just like Alexander the Great or Julius Caeser...
Israeli archaeologists wandered the Sinai peninsula for 15 years from 1967 to 1982 when Israel occupied Sinai. They couldn't find any evidence of Moses or his 2 million followers that escaped from Egypt 4000 years ago (No garbage heaps without pig bones as found in archaeological sites in Israel). Although they did find evidence of 100 people who crossed the Sinai about 70,000 years ago.
The story of Moses does not exist in older versions of the Jewish bible. According to the manuscripts that have been recovered from various times the story of Moses appears in the Jewish bible around 800 bc, this was a time when the kingdom of Israel was at war with the Egyptians, so most probably Moses story was a forgery that was entered into the bible as a war time propoganda against the Egyptians during their war against the Israelites.
Interesting thing is that there are many religions that have characters that fit the description of Jesus and Moses perfectly, such as Lord Krishna, Horus, Paris of Troy among many others and their stories were written thousands of years before Jesus or Moses, so most probably the Jews and Christians copied those stories from other religions. There is a consensus amongst historians that Moses and Jesus are not historical characters but rather mythical characters.