In the SEO world, crawling means following your links and “crawling†around your website. When bots come to your website (any page), they follow other linked pages also on your website.
indexing is the process of adding webpages into Google search.
Depending upon which meta tag you used (index or NO-index), Google will crawl and index your pages. A no-index tag means that that page will not be added into the web search’s index.