The birth date can mean various things. The energy represented by two of the numbers that can be calculated with the birth date are the life path number and the birth day number. The first is the full day-month-year date. The second is the day number.

Those links will provide a lot of information.

Other personal numerology chart numbers calculated from the birth date include the challenges, the pinnacle cycles, and the life period cycles. Those tend to have much influence on the types of situations and circumstances a person encounters as they live life.