That's right. Immersion is necessary. The Apostle Paul taught that being immersed in water and coming out again is symbolic of death, burial, and resurrection. Roman 6:3-5 states it.
In the New Testament, The Lord gave the instructions to His Apostles- Baptism. Matthew 28:19-20 explains that. If one has a faith in Jesus Christ, repent, and is baptized, sins are forgiven through the Atonement of Jesus Christ. John the Baptist did baptize in the wilderness, and preach the baptism of repentance for the remission of sins- Mark 1:4. There are two more verses- Acts 2:38 and Acts 22:16 said the same thing.
Jesus Christ was without sin, but he said that His baptism was necessary to fulfil all righteousness- Matthew 3. He asks all of us to follow him and do the things we have seen him do-
Now, it is up to everyone to make a choice. That's it.
