Adding background music to your videos is essential for engagement, but many free apps (like CapCut, InShot, or KineMaster) leave a watermark unless you pay. This guide covers 100% free, watermark-free methods for desktop, mobile, and online. Key Principle: Use Software That Doesn't Force Watermarks Avoid: "Free" mobile apps that add logos (unless you pay). Choose: Open-source software, built-in OS tools, or specific online tools with clean export. Method 1: Desktop (Best Quality, No Watermark) A. DaVinci Resolve (Professional & Free) Best for: High-quality videos, precise audio control. Watermark? No.