Question

how does the haploid cells formed during meiosis but why it is not happening in mitosis?

Answer 1

After mitosis two identical cells are created with the same original number of chromosomes, 46. Haploid cellsthat are generated through meiosis, such as egg and sperm, only have 23 chromosomes, because, remember,meiosis is a "reduction division." Makes all cells other than gametes.
Meiosis produces 4 haploid cells. Mitosis produces 2 diploid cells. The old name for meiosis was reduction/ division. Meiosis I reduces the ploidy level from 2n to n (reduction) while Meiosis II divides the remaining set of chromosomes in a mitosis-like process (division).