If food is hot after cooking the food you should allow the food to cool down for at least 30 minutes before refrigerating.
The food does not need to cool down completely before refrigerating but you should allow the food to cool down somewhat so that the food is not really hot.
If you put too hot of food in the refrigerator it can cause the other foods to get warm as well and also makes the refrigerator run longer to cool down the food.
So as long as you allow the food to cool down for 20 to 30 minutes before refrigerating the food you'll be fine.
I have placed hot food in the refrigerator when I had to leave the house immediately for an emergency and the food and the refrigerator were just fine.
But if you have time allow the food to cool down some before refrigerating it.