Hsve you extended any times that are near the page edge out past the page area?
For example, go to File>Document setup and show options
Insert the bleed amount (in this case 1p6 all around)
You will notice that in Normal Mode there is a thin red line around your pages.
Any items that require bleed need to extend to this line or past it.
Please also change the offset of your crops to 2p0
No the red area is just a guide, it does not need to appear on the pdf,
you can include it if you select Visble Guides and Grids, but that also includes the margins, which you definitely don't want to appear on the PDF.
If you want a red frame in that area I suggest you draw a rectangle on the master page in around the red area.
Apply a red stroke, very thin
Then export the pdf.
I don't recommend this.
The only thing that should be in the bleed area is artwork that needs to extend into the bleed area. If you insist on putting things in the bleed you run the risk of it appearing on the final print.
That's why I say to set the offset of the crops so it sits outside the bleed area.
Crop marks are needed to trim the page to size when printed. As printers can't print right to edge of a sheet, and that it's near impossible to trim a sheet of paper right to the edge of a colour - the colour needs to extend past the crop line, this is called bleed.
When you bleed the document, i.e., extend any item that is tucked right against the foredge (the edges opposite the spine), then you need to extend this object off the page into a "bleed" area.
This allows for human error when trimming the paper, as each sheet is not trimmed individually (that would take forever!) they are stacked on top of each other and trimmed in stacks. It would be impossible to stack all the sheets exactly even, and there is movement on the press, so compensating for the movement and the fact they can never be stacked exactly even - for this reason you need objects to extend past the edge of the page.
The crop marks tell the guillotine operator where to trim the sheet. Once they have the measurements in their guillotine machine it's a simple matter of rinse and repeat with as many stacks of paper there are.
And printers can sometimes fold and trim a print job folding machine, and since it's a machine and you have to account for mechanical errors and human error, you need bleed too.
Bleed is important - If you don't add bleed then the object stops at the foredge of the paper. And if the blade trims/crops close to the object but misses by a sliver - then you have a sliver of white on the printed piece, which is highly undesirable.
So you need crop marks so the printers know where exactly to cut the paper, and to cut into the bleed so that you don't have slivers of white.
And yes you need crop marks even if you don't have bleed, if you don't have any bleed it's likely that the edges of the paper are just white, so there are no markings where to cut to give the correct size that you want. So crop marks need to be included no matter what.
And the placement of crop marks is important. As I said earlier, crop marks are for letting the guillotine operator know where to trim the page so that it cuts into the bleed area. The bleed area to allow for mechanical, physical and human error. And seen as the bleed can sometimes be included in a final printed piece it is not desirable to have anything other than bleed objects in the bleed area.
For this reason you offset your crop marks to be outside the bleed area. As I'm in Europe I work mainly in millimeters, so I would set my Bleed Area to be 5 mm and I would set my crop marks to Offset by 6mm.
This ensures that the crop marks do not encroach the bleed area. If your crop marks do encroach the bleed area you run the risk of the crop marks appearing on a final printed piece.
So in Summary
Make sure you have bleed where necessary on your document.
Add the desired amount of bleed - in my case 5mm.
Offset the crop marks so they don't encroach the bleed area - in my case 6mm.