Mantra is a word or phrase that is chanted to link up with the ECK, the Divine Spirit.
HU is the most sacred mantra that can help souls to find spiritual solutions to their problems. You can sing that for fifteen minutes daily or when you are in need of help.
Wah-Z, chanted as Wah Zee, is the spiritual name of the current Mahanta. It is another mantra.
There are other mantras that can be used to reach a specific goal. For example, Mana to review previous reincarnations.
Chanting a mantra or your secret word is a form of Spiritual exercises.