Authentication and legalisation services are easily available at almost 1,000 post office marked with the Czech POINT logo; you don’t have to visit any authority or notary any more.
If you want to have a document authenticated, you don’t have to bring a copy of the document: it will be copied (up to the maximum A4 format) by the post office personnel.
You can have your documents authenticated and, for instance, pay your money orders and pick up your letters at one visit.