Bleeding 3mm
The part of image area that prints beyond paper edge will be trimmed during final trimming.

Safe Margins 5mm
In addition to bleed, you should also add a margin to the edges of the document to avoid having your objects looks as if they are about to fall off the page, or get cropped off when the document is trimmed. We recommend 5mm or above.

Photoshop, Microsoft Word & Publisher user
Those application without page bleeding function.
Any graphic or image print to the edge of the page.
User must enlarge "Document set up" to make bleeding.

Extra 3mm on each side