Both mitosis and meiosis are a kind of cell division.
In mitosis, you get 2 daughter cells at the end. The parent cell duplicates all its chromosomes before dividing. This leads to that the daughter cells are genetically identical to the other daughter cell and their parent cell. We call these cells are in a diploid condition. They have to complete sets of chromosomes for that organism. This is common in body cells. They're important for growth, repair, etc.
Meiosis is the cell division that leads to 4 daughter cells at the end. However, they are not genetically indentical to each other. The parent cell first duplicates its DNA and divides, just like mitosis, but the 2 daughter cells divide again into 4 daughter cells but without duplicating it's chromosomes. Therefore, the 4 daughter cells only have half of their chromosomes comparing to their parent cell.
These cells are haploid. They're found in gametes, which are necessary for sexual reproduction.
To conclude, we can say mitosis is the kind of division that leads to genetically identical cells and meiosis leads to genetically differnt cells. The end product of mitosis is 2 cells less than meiosis, but they're genetically identical to each other, unlike meiosis.