Set Up Bleed

If setting up a new document

• Select File/New
• Change Units to Millimetres
• Change Bleed to 3mm
• Change Colour Mode to CMYK Colour
• Set Raster Effects to High (300ppi)

If you already have a document, 

1. Click off the artboard
2. Select Document Setup
3. Set Bleed to 3mm, and click OK

• A red bleed line will appear around the Artboard
• Extend background colour to the bleed line

• Extend the background colour to the bleed line

• Save with the appropriate PDF Preset
  (See how to set up a PDF Preset)