Traditionally we would use a special bacteria that can put its DNA into plants.

We would first find a gene we think would be helpful for growing plants and then copy it. Then we would put that gene into the bacteria.

To make sure the bacteria are successfully putting the gene we want into a plant (and not something else) we add an herbicide resistance that comes with the desired gene, so only modified plant cuttings survive. The plant cuttings grow up and are tested again to make sure they also have the desired gene and not just the resistance.

CRISPR, like another person mentioned, is no more a machine than you or I. CRISPR is a protein with some guiding RNA that tells crispr to cut DNA at specific spots, allowing us to squeeze in a gene at the cut spot.

Bacteria doesn't do the inserting, and we have more control over exactly what and where a gene is put into a plant's genome.