The quiet zone for standard products is 4 mm from all trim edges and folds, shown on the templates as a blue area on the QUIET-ZONE layer.
For Large Format products and booklets, we recommend a larger Quiet Zone of 10 mm.
Any elements that use the QUIET-ZONE (near the trim edges of the artwork) risk being cut off, or will look untidy after guillotining. Avoid placing text in margins, unless you want it to ‘bleed’ off.

In our InDesign Templates, we show quiet zones in blue:

The use of designed margins or uniform borders near the product edge is strongly discouraged, because guillotine cutting is not accurate enough to ensure that margins will be of the same width on every edge. Even a 0.5 mm movement in the guillotine blade will make the margin look uneven.
If you must use a border, keep it at least 10 mm from the trim edge.
If you have background or picture elements entering the quiet zone, be sure that they bleed fully through the quiet zone to the edge of the artwork.