I got really confused with this. I read a lot about this, but yet can't be sure. I'm trying to make A4 document(graphic design work, not text-only doc.) for print. The problem is I don't know who is printing this(no idea how, in what printer etc), but I got twice my document with white spaces in sides(up-down and left-right). At the first one, I didn't know about crop marks and bleed, and the file size was original: 210x197mm and 300pix/inch resolution. In the second, I add an extra space(with graphics) to the edges.
Now, I need it to be done for sure, but I'm not really sure again :( I add again extra space to edges(5mm each edge, in total 10mm sides, 10mm height) and used graphics to fulfill this extra space. Plus, I did black crop marks as was explained here(some tutorial at youtube) but I don't know how printer works, because the color of this crop marks is black, but at two of the sides I have a background dark as well(#5c0d0d), so I don't know if it will cut it as I want it or not(by this crop marks). I can't add an image of the work, because of the terms etc, but I did the image of the corner: