How to Add Schema Markup in WordPress, Shopify, Wix, HTML & More (2026 Guide)

Learn how to add schema markup across WordPress, Shopify, Wix, Webflow, HTML, Squarespace, and Next.js. This 2025 guide covers 11 proven methods to implement JSON-LD correctly, validate structured data, and boost SEO, AEO, and AI search visibility. Avoid common errors, enhance rich snippets, and make your content AI-friendly and search-ready in minutes.