The Catechism of the Catholic Church (CCC) says:

In the most blessed sacrament of the Eucharist “the body and blood, together with the soul and divinity, of our Lord Jesus Christ and, therefore, the whole
Christ is truly, really, and substantially contained.”   CCC # 1374

There is more to this than I can understand or explain, but let me focus on one part of it. “the … soul … of our Lord Jesus Christ … is … contained.  CCC # 1374

This is a part of the mystery that I can relate to because I have a body and a soul.
The collection of molecules typing these words is my body.
Why is this particular set of molecules my body?
Because it is soft and pink like my tongue?
Because it is hard like my fingernails?
Because it is brown like my eyes?
No!
It is not color or texture or any physical property that makes this collection of molecules my body. In fact, scientists tell us that in seven years, every molecule will have been replaced, yet it will still be my body.

This collection of molecules is my body because my soul lives within this collection of molecules. Similarly, a lowly piece of bread becomes the body of Jesus when the soul of Jesus occupies the bread.

The creator of the universe; Lord and master of all that exists, Jesus, wants you to share in His life. Jesus wants to be in Communion with you. To renew your communion with Him, He is willing to humbly put His soul into a piece of bread that you can merge into your body. How much clearer could God make it than to let you put Jesus’ soul where your soul is?

Through His church, God has given you the gifts of the Sacraments. We were all in perfect communion with Jesus right after we got Baptized. By putting His soul into a mere piece of bread, Jesus gives you the opportunity to receive His body and thus RENEW your communion with Him.

Explore the meaning of Communion here