WordPress powers 43.5% of all websites — and WordPress SEO has changed dramatically since 2022. This complete 2026 guide covers the best SEO plugins (Yoast vs Rank Math comparison), site architecture, on-page optimisation, E-E-A-T signals, Core Web Vitals fixes specific to WordPress, and the GEO layer for AI search visibility — with every plugin, tool, and official documentation source linked throughout.