I am looking for info on how to make a brick fireplace smooth? How or what products do I need to make that possible without it cracking?

I'm not sure exactly what you are meaning about making it smooth. As you asking about the mortar used between the bricks or about the actual surface of the bricks themselves?

I'm not sure exactly what you are meaning about making it smooth. As you asking about the mortar used between the bricks or about the actual surface of the bricks themselves?
I'm sorry I was asking how or what can I use to cover the bricks and make it look like a smooth wall? Instead of a brick wall.

You could cover it up with drywall or use wire mesh / plaster, which would be much more difficult. The wire mesh would prevent it from cracking.