How do I split a large sitemap?

Split a large sitemap by content type, by section, or by URL chunk, then reference all the children from a sitemap-index. By content type is the cleanest: one child sitemap per pages, posts, products, categories, images, videos. By section works for multi-region/multi-language sites: one per locale. By URL chunk is the fallback — chunk URLs into groups of, say, 5,000–10,000 each. Keep each child well under the 50,000-URL and 50 MB per-file ceilings. The sitemap-index lists each child with <sitemap><loc> entries. Submit only the index URL in Google Search Console — Google fetches every child automatically. WordPress (Yoast/Rank Math), Shopify and most major CMSes generate this split automatically when needed.