Bleed, Margin, and Trim
A. Trim size is indicated final size of your document. It should specify where we will cut.
B. Bleed refers to the printed space beyond the trimmed edges of a printed document. This extra space allows for any slight position variations on press or during cutting. Artwork and background color should extend into the bleed area to ensure no unprinted edges appear on your finished piece. A bleed size of .125" to .25" is acceptable.
C. Margin is the safe area around the trim edges of your document. Placing art or type to close to the trim edge may result in unexpected results due to slight variations on press and/or cutting. We recommend at least .125" margin, .25" to be safe.
Learn more about bleed, slug, margin and trim from Adobe