What are sitemaps?
A sitemap allows webmasters to submit to search engines a list of crawlable resources for indexing.
Sitemaps can contain information including the location of resources, the relationship between resources, and the last time a resource was modified.
Sitemaps can contain Hreflang information, allowing webmasters to notify search engines of language/location relationships between resources.
Types of sitemaps
There are multiple different types of sitemaps used in SEO/on the web:
XML Sitemaps, HTML sitemaps, Image sitemaps and Google News sitemaps.