In most cases, you will need some instruction about 3D printing, in general, and how your particular model works. However, companies are moving towards more user-friendly designs. Moreover, you have very detailed user manuals that can help beginners set up and use a 3D printer.
If you’re buying an expensive 3D printer, you should perhaps have a professional or experienced person operate it. You can always contact the tech support of the brand to help answer your questions.