The first question is what was the breeder feeding and why do you feel like you need to change it?
But, presuming you really want to, the best food is the one that works best for you and your puppy. You’ll read many places about human-grade ingredients, excellent quality ingredients, kibble and canned and frozen, or how a home-made diet is the best and healthiest, but not everyone has the time or experience to create and package their own home made diet! That means you’ll need to read many labels and compare the ingredients and quality there. This – – is a good site that will give you a lot of information about what to look for and what you are looking for. Plus the site is NOT run by a dog food company so it’s pretty impartial.
Do look for quality ingredients – “by-products” aren’t the best when they contain chicken beaks or pig tails! Take advantage of sample packages of good foods and see what your baby likes to eat – it certainly makes it easier when your dog wants to eat the food! But results are what really matter – and you do want a shiny coat, clean teeth, and small dry stools. Too much “going out” is a sign that your puppy isn’t digesting all the nutrition in the food.
There is no one single good answer. Otherwise there’d just be one single good dog food! Good luck on your search.