No, you do not have to use a clicker to do Puppy Culture.

You can use a verbal marker instead (such as "yes" or "right") or a "tongue click" noise instead of a clicker. 

However, you may find that using a clicker is easier once you get the hang of it! The clicker is more precise to use than a verbal marker.

If you're a breeder, be sure to let your puppy owners know which you taught so there's no confusion in the new home.