Most people think that their new and fluffy puppy shouldn’t be walked on a lead until it’s quite a bit older and bigger. This is true to a certain extent but you can certainly introduce your pup to the lead prior to his/her initial walk.
Whilst your puppy is still indoors pop a very soft collar on them. Leave it literally for about five minutes and if there is no major reaction praise and offer a treat as a reward. By major reaction I mean throwing a bit of a ‘wobbly’ whining and running around etc, etc. Most puppies will display minor signs of discomfort or slight concern at the strange object placed around their neck. You’d expect some indication of knowing the collar’s there. Perhaps scratching at it or zooming around in circles whilst trying to remove it or rubbing their head against an object or along the floor.