Definition of PageRank
PageRank is an algorithm used by Google to measure the popularity of a site or a web page.
It's a system that was invented by Larry Page, who is none other than the co-founder of Google.
But if PageRank is linked to the notoriety of a site and its popularity with other sites and Internet users, what criteria are taken into account to say that one site is more popular than another?

The PageRank algorithm makes use of in particular links to a site.
The more links there are pointing to a web page, the better it will be rated.
But the PR (PageRank) rating doesn't just take that into account.
Indeed, Google's algorithm also studies the quality of sites that talk about a site and that use these outgoing links.
So, the more people who talk about a site, the higher the PageRank will be.
And if you want to know your ParegRank index, then there are several tools that allow you to calculate it online, the most famous being “Google Bar”.

The first page of Google's search results displays the highest-rated pages for a given query and the best natural results appear in first position.
Like
People Also Ask , Google has chosen to extract from the first results a suggestion that it chooses according to certain criteria and it places it above the rest, that is to say in position 0 .

If it is essential for the SEO to position the page for which he is responsible in the first SERP (Search Engine Result Page) of Google for a given request, how much more important is the fact of being able to position it in position zero.
Note that position 0 is the location between natural results and sponsored links and that it gives a page the opportunity to be featured in addition to already appearing in natural results. The display of the extract of the site in position zero gives this site the maximum chance of being clicked, and therefore visited, and therefore of benefiting from increased traffic. This framed synthetic extract includes the Featured Snippets or optimized extracts, the Knowledge Graph which is a structured information sheet as well as the Quick Answers or results from Google Onebox, The advantage of appearing at the top of the page is all the more Important than on mobile devices, the display of featured snippets almost occupies the first page of results.
In addition, this advantage counts in the results of voice searches.
But the competition is obviously tough for the countless sites and their countless referrers.
Google has established some rules making it possible to claim this coveted position but the content of which, however, could satisfy the Internet user to the point of no longer making him want to click on the proposed links returning to the source site.

Certain conditions must be met by a site for it to have the chance to be designated among many others by Google to occupy position zero. In short, it must clearly show the fact that it is above all user-oriented. It is necessary that in relation to the request on which it is positioned, the site has at least one page containing a short answer, totally relevant and which appears preferably in the first lines of the text.
This involves having high quality, unique editorial content of around 1000 words and a paragraph of around 45 words including the query.
The use of tools such as Answerthepublic and Ubersuggest makes it possible to identify the most frequent questions relating to a keyword and to generate the keywords of interest in order to formulate the most effective answers in terms of search.
That the main request appears in all the salient parts structuring the text such as the title and sub-titles is not to be neglected.
The page must also have a lower than average loading time.
Finally, Google must already locate this page in its first organic results.
In addition, you should know that a page chosen in position zero is a page optimized for mobile users among others.
It should be noted that these conditions are not exhaustive.