what is the difference between indexed and crawling?

Crawling and indexing are two distinct things and this is commonly misunderstood in the SEO industry. Crawling means that Googlebot looks at all the content/code on the page and analyzes it. Indexing means that the page is eligible to show up in Google's search results.
Crawling is the process or reading through your webpage source by search engine spiders. They provide a cache certificate after a successful crawl. Indexing is updating the cached webpages in search engine database. Indexed webpages are now ready for search engine rankings.
Crawling and Indexing, both are the important activities of Google Search Engines. To illustrate, Whenever you post a fresh content on your website, the google crawlers crawl that content and analyze it. and after crawling, google bots indexed it or store it in its memory so that they can display that content in the google's search engine result pages.(SERPs).