I am using https://doc.sitecore.com/search/en/developers/search-developer-guide/getting-started-with-sitecore-search.html link to learn about Sitecore search and have couple of questions related to Sitecore search for XM cloud platform

1. How is indexing different in Sitecore search than Solr indexing ?
2. Can we use computed index field in Sitecore Search like Solr, if yes, how? If no, do we have any other substitute for it? Please let me know if there are any other useful links and videos on Sitecore Search used for XM cloud platform.