A URL (Uniform Resource Locator) is the web address that tells a browser where to find a specific resource — a page, image, or file — on a server. It stitches together a protocol, a domain, and a path, for example https://www.seologist.com/products/technical-seo.html.
Reading that example left to right:
Longer addresses may also carry a query string after a ? (used for parameters like tracking tags) and a fragment after a # that jumps to a section within the page.
A clean, readable URL helps both people and crawlers understand a page before they open it. Compare /blog/on-page-seo-checklist with /blog?id=48823&cat=7 — the first previews its content in the search result and in a shared link; the second reveals nothing. Keep slugs short, lowercase, and hyphen-separated, avoid stuffing keywords, and settle on one canonical version so the same content isn't split across trailing-slash or parameter variants. These conventions are foundational to sound website structure.
They have a small, mostly indirect effect — a descriptive slug improves click-through and clarity more than it moves the ranking itself.
Only with a purpose and a 301 redirect. Needless URL changes risk lost equity; when you must restructure, map every old address to its new one. A review through technical SEO keeps those migrations safe.