Cells with 23 chromosomes are produced through meiosis, not mitosis.
Meiosis is the process of cell division that occurs in the formation of gametes (sperm and egg cells) in sexually reproducing organisms. During meiosis, a diploid cell (with 46 chromosomes in humans) undergoes two rounds of division to produce four haploid cells, each with 23 chromosomes.
In contrast, mitosis is the process of cell division that results in two identical daughter cells, each maintaining the same number of chromosomes as the parent cell. In humans, this would involve the division of a cell with 46 chromosomes into two cells, each also having 46 chromosomes.
Therefore, the presence of cells with 23 chromosomes indicates that they are the result of meiosis.