Whoever baptizes you needs to hold the priesthood—the power to act in the name of God. When Jesus wanted to be baptized, He went to John the Baptist, who had the priesthood (see Matthew 3:13).
The person who baptizes you will get permission from your bishop or branch president.
Jesus was baptized by immersion, which means He went completely under the water and quickly came back up again (see Matthew 3:16). This is how you will be baptized. Being baptized this way reminds us that we are leaving behind our old life and starting a new life dedicated to serving God and His children.
When you are baptized, you make a covenant, or two-way promise, with Heavenly Father. You promise Him that you will do certain things, and He promises to bless you. This covenant is described in the sacrament prayers that are said each Sunday (see D&C 20:77–79). You promise:
To remember Jesus Christ.
To keep His commandments.
To take upon yourself the name of Christ, which means to put His work first in your life and do what He wants instead of what the world wants.
As you keep this promise, Heavenly Father promises that the Holy Ghost will be with you and that your sins will be forgiven.
The gift of the Holy Ghost is one of Heavenly Father’s most precious gifts. Your baptism by water isn’t complete until men holding the Melchizedek Priesthood give you a blessing to receive the Holy Ghost (see John 3:5).
The Holy Ghost is a member of the Godhead. He testifies of Heavenly Father and Jesus Christ and helps us know what is true. He helps us be spiritually strong. He warns us of danger. He helps us learn. The Holy Ghost can help us feel God’s love.
When you are confirmed a member of the Church, the Holy Ghost can be with you always if you choose the right.
The Lord teaches that children shouldn’t be baptized until they are old enough to understand the difference between right and wrong, which the scriptures say is eight years old (see Moroni 8:11–12; D&C 29:46–47; 68:27).