SEO is the process of improving the volume or quality of traffic to a web site from search engines via search results. In other words, SEO involves making sure changes to your website style and content that make your site additional enticing to a search engine. you are doing this in hopes that the search engine will show your web site as a top result on the search engine results page. 

In order to do this, search engines can scan, or crawl, different websites to raised perceive what the site is about. This helps them deliver a lot of relevant results to those that are looking for bound topics or keywords. Similarly, the search engines can scan the site to determine how simple it's to navigate and skim, rewarding user-friendly sites with higher rankings on the search engine results page. 

There are several advantages of SEO for your business. By up your SEO, you'll work to expand your visibility on the search engines. This helps you reach and have interaction with a lot of potential customers. By making a lot of partaking and effective SEO-focused content, you can increase your possibilities of bringing in more targeted organic traffic.

The most popular search engines are Google, yahoo, bing, etc.

In the SEO world crawling means following your links around your web site. In the crawling process google visit your website for the tracking process, this process is done by Google spider crawler.

The process of indexing done after crawling. Indexing is the process of adding web pages into Google search.

Queries & Keywords in Search engine Optimization?

Queries are related to the users, those who want to search something on the web, they will open any search engine and type  search query about what they want to search 

eg.what is SEO, learn SEO, full form of SEO

The keyword is a specific word that users are looking for on the web. In the above example, a user wants to know about SEO so that is your keyword.