A monument proof is the drawing you approve before the stone is cut. A lead designer prepares it. You will hear it called a CAD proof, or CAD drawings. It shows the form of the memorial and the layout of the lettering you asked for.
Read it slowly. Check the spelling of the name, the dates the family agreed to use, and any short line under them. Check that the form matches what the cemetery site check allowed. Your project manager is the person you talk to if something should change. The lead designer is the person who produces the drawing.
Approval is the submittal. Nothing is cut until you approve it. When you approve the CAD proof, that drawing becomes the shop drawing. The shop drawing is the final approved drawing that goes to fabrication. The shop cuts, polishes, and engraves from that drawing.
The proof is the layout on the page. Lettering on a polished stone, in sun and in shade, can read differently than the same words on a screen. Look at the words themselves before you approve. Changing them on the drawing is a different job from changing them after the granite is cut.
This approval sits in the middle of the project. The meeting before it is what the design consult is for. The full order of the work is where the proof sits between the consult and the setting. After the shop builds from the shop drawing, the stone is set and walked through.