Robots.txt, is a text file present in the root directory of a website. The Robots.txt file is a convention created to direct the activity of search engine crawlers or web spiders.

Robots.txt is a text file you put on your site to tell search robots which pages you would like them not to visit. Robots.txt is by no means mandatory for search engines but generally search engines obey what they are asked not to do. It is important to clarify that robots.txt is not a way from preventing search engines from crawling your site.

make sure you include your sitemap in robots.txt

Also, block your privacy policy and terms of use to be blocked in robots.txt

Robots.txt files inform search engine spiders how to interact with indexing your content.
By default search engines are greedy. They want to index as much high quality information as they can, & will assume that they can crawl everything unless you tell them otherwise.wlers.