When you're first starting to feed the puppies puppy food you should start giving them wet puppy food until they get their teeth in fully.
So around 3 weeks of age you can start feeding the puppies some wet puppy food and then as they get older you can introduce them to some dry puppy food.
The wet puppy food will be easier for the puppy to eat and digest than the dry puppy food will be until they get their teeth in fully.
Once the puppy gets their teeth in fully then you can feed them dry puppy food.