The name of the city is "PRAHA". In some languages, they change original geographical names, to a spelling and pronunciation considered easier in the language of the speaker. Unless it is something really unpronounceable, I believe it is not appropriate to change the original geographical name to whatever is more comfortable to you. Prague in English, and Praga in Spanish, are widely used. I propose these places do not exist. The city you can actually visit is called PRAHA.
Something similar happens with other places, like LONDON. This is an actual place, a real city. However, speakers of French and Spanish call it "Londres", each with their own pronunciation, far from the real name: "London".