The Bible teaches that every Christian is to be baptized (Acts 2:38).  We are to be baptized to identify ourselves with the Lord (Matthew 10:32) and to follow the example of Jesus who was also baptized (Mark 1:9). Biblical baptism involves three important elements:

Following conversion

Every example of baptism in the Bible happened after a person received Christ as their Lord and Savior (Acts 2:41, 8:35-38, 16:14-15). In fact, baptism is the first step of a new Christian’s life (Acts 10:43-48).

By immersion

The Greek word for “baptize” means to submerge or dip under water. The Bible is clear that baptism symbolizes the death, burial, and resurrection of Jesus Christ and our old way of life (Romans 6:3-4, Colossians 2:12), which can only be done visually by the process of immersion.

As a symbol of salvation

Baptism does not get you into heaven (see “Salvation”). It is a one-time act of obedience and faith that symbolizes the salvation that is already ours through Jesus Christ (2 Corinthians 5:17). It is comparable to a wedding ring that symbolizes the marriage. 
Although it is only a symbol, it is clearly an important one as the church is commanded to “go into all the world and make disciples of the nations, baptizing them in the name of the Father, Son, and Holy Spirit…”  (Matthew 28:18-20).