To be exact,moshi moshi means excuse me.
This word is kind of an ancient word.
So, many japanese don't know ｔrue meaning. Here is something interesting I found about "moshi moshi".
Moshi Moshi (MOH-shee moh-SHEE) (myth reference)
exp. - Commonly used to answer the telephone in Japan, this expression has no real meaning, with the cloests translation of the term being "hello?" when receiving a phone call. The term itself stems from a Japanese myth of the shape-shifting fox. The fox is a creature of supernatural powers and mystery in Japanese tradition. They are said tosometimes change their form to that of a woman in order to seduce men for benevolent or malicious intent. The term "Moshi, moshi!" has no intrinsic meaning. It is a phrase supposedly foxes cannot pronounce. Therefore, if you say this over the phone and receive a reply the person you are talking with is not a fox in disguise.
Good luck with work & school :)