There's really no set amount of times that a toddler should poop in a day and it depends on the toddlers diet.
If the toddler doesn't eat enough fiber containing foods then the toddler may not poop at all for a few days or may only poop once per day.
If the toddler eats a lot of fiber based foods then the toddler may poop once or twice per day but as long as the toddler is pooping once every 3 to 4 days then they're likely not constipated.
If the toddler goes longer than 4 days without pooping then it's possible the toddler could be constipated and needs to drink some apple juice, prune juice etc to get their bowels moving.
If that doesn't work then the doctor may prescribe a laxative for the toddler if they're constipated.
Sometimes you have to remind your toddler to go to the bathroom because they can get so caught up in playing and be distracted as well.