Why do you need bleed in printing?

Bleed is the margin needed for the cutting process. When preparing a file for printing, we extend the design 3 mm beyond the edge of the page.

We use crop marks to indicate where the document should be cut. This is necessary because printed materials can never be cut to an accuracy of 0.1 mm.

If you don’t add a bleed to a document, there is a good chance that a white border will remain visible around it and of course we don't want that.