The main place to visit Prague is the Old Town Square, which is located in the center of the Stare Mesto district.
In this area, most people accumulate: tourists and onlookers.
There are various free entertainment and performances. Most travel agencies offer their services: the opportunity to buy this or that excursion. Before buying from the first one, look at everything, as the cost changes, and you can see more and more interesting things on other excursions. Of course, I also offer individual ones, where they will tell you more interesting things and much more.