What does the Bible say about burials?

The Bible is silent on matters of burial. In fact, the Bible makes clear that after we die, our physical body is a meaningless vessel destined to return to the earth one way or another. Therefore, Christians should place little or no interest in the final disposition of a dead body except that we attend to its disposal in ways that comfort the living. If a body is missing, a Christian family has liberty in Christ to conduct whatever ceremony they desire (or none at all). As Jesus told one of His disciples:

Matt. 8:21  Another of the disciples said to Him, “Lord, permit me first to go and bury my father.”
Matt. 8:22  But Jesus said to him, “Follow Me, and allow the dead to bury their own dead.”

You may also find the following articles helpful:
Biblical Burial Requirements
Cremation or burial?

Scripture quotations taken from the (NASB®) New American Standard Bible®, Copyright © 1995, 2020 by The Lockman Foundation. Used by permission. All rights reserved. www.lockman.org