Prep Magazine for Edge-to-Edge

I have a finished magazine laid out in Adobe InDesign, but when I print it on A4 paper a thin white border still appears. I need you to open my .indd file, apply the proper bleed and trim settings so every page prints full-bleed, and then export a press-ready PDF that a commercial printer can drop straight into production.

Scope of work
• Adjust the document size to exactly 210 × 297 mm (A4) and add the standard 3 mm bleed on all sides.
• Extend any background images, colours, or graphic elements that should hit the edge so they reach into the bleed area.
• Check linked images for resolution (300 dpi preferred) and relink if anything is missing.
• Update master pages and page numbers so nothing is clipped.
• Export a print-ready PDF/X-1a or PDF/X-4 with the bleed included and no unwanted white margins.

Deliverables
1. The corrected InDesign package (indd, links, fonts).
2. A single print-ready PDF that shows crop marks and bleed when previewed.

If you know your way around InDesign’s print presets and have prepared magazines or books for professional presses before, this should be a quick job.