You should ask the breeder or pet store where you got your pup for some advice. Puppies have large energy requirements for growth and activity and need a good quality high density food. Feed a high quality commercial puppy formula. This will contain all his nutritional requirements and you should not feed any snacks or table scraps. They have small stomachs so they should be fed frequent small meals. From 2-3 months they should be fed 4 times daily. From 4-5 months 2-3 times daily and from 6 months they should be fed twice daily.
Good quality dog or puppy food depending on the age. Make sure that the first 3 ingredients are meat products and not fillers. I recommend mostly dry food because Maltese are prone to dental problems. I am not sure about poodles but it is best to use the dry food to help clean the teeth.
Why do you need to feed your poo?