Whenever the idea of total submergence was to be expressed, whether literally or metaphorically, baptizein was the word used. As you read the Bible, mentally translating the word baptize to the word immerse will greatly help your understanding. Not every time the word baptize or baptism is used in the Bible refers to water baptism. Water baptism is your public declaration of your death. By being baptized in water you are saying that you have died to sin, selfishness, and the world's ways.
Water baptism is a public burial of the old life.
By asking for burial, you declare that you believe something has died. There is no need for a burial without a death. Burial is not absolutely required, but is recommended as the best course of action. So, generally, those who receive Jesus Christ should normally be baptized in water. In the book of Acts, water baptism always seemed to be done without delay.