If you plan on leash walking your Labrador puppy, training him to heel while he's still little is a great idea so when you have an older, much larger Lab on your hands he will understand your expectations. Your Lab can have great leash manners and will be walking beside you at your pace instead of running ahead pulling on the leash or allowing himself to become distracted, chasing something along your path. Training a dog to heel is imperative for dogs who are going to be walking with their owners on leashes often.
Once your Labrador puppy understands the heel command, you can take him out on walks around your neighborhood, through parks, hiking, and even near other dogs or animals with a realistic expectation that he will know how to behave and will stay with you on command. Train your Labrador puppy to heel while he's a puppy and set him up for a lifetime of beautiful walks together.
The 'heel' command is not a difficult command. However, it does take a lot of practice and some maturity from your puppy. Maturity will develop as you are practicing together and your puppy grows and ages. Training the 'heel' command can happen a few different ways, from inside away from all distractions, to outside, or walking along a wall or a fence so your dog has nowhere else to go on leash. You can even train your puppy to heel off-leash if you want him to stay near you but without the confines of a leash. Puppies are great candidates for learning commands such as 'heel' because they are young, eager to please, and highly energetic. Don't expect your puppy to be able to go on long walks with you while leashed because he probably won't have a long attention span for a few more months. This short attention span makes short burst training perfect because you will have his attention long enough to train a command in short sessions and reward him for positive behaviors.
Before you begin to take your Labrador puppy out for walks, be sure you have an appropriate leash and collar for his size. If your Labrador puppy is going to be larger than you can handle as an adult, consider putting him in a harness now as a puppy, so he is used to the way this feels when he's older. Harnesses make walking strong, overpowering dogs much easier on the owner than having a leash attached to only a collar. You will also need to be prepared with lots of little tasty treats when you train your puppy on your walks together. Put these in a bag attached to your leash or person so they are handy for quick rewards. Because of your pup's attention span, keep your training sessions with him short.