Yes, it is possible to print on both sides. The back is a second run in the machine and this one will be invoiced in supplement.
In typography, it is also possible to perform the following actions:
– on 300g papers only: creasing (to fold the paper), embossing (an additional mold must be counted),
– on 600g cotton (and possibly 360g paper): letterpress (printing with more machine pressure),
– on all papers: perforation, cutout with rounded edges or with a specific cutout shape (you will also have to add the cost of the cutout shape).