These are the positions that any website owner strive for as they are trusted more than adverts and are put there on merit. Some may do their own SEO if they have sufficient knowledge on how to perform it on their sites. Some will employ seo services to do it for them.
Search engines will display websites to a searcher that it thinks are good enough and represent exactly what the searcher has typed in the search box.
The algorithms will in milliseconds analyse, compare and judge which sites you should see first. The reason the go to so much trouble and effort is they want to deliver the very best results to you so you will get the information that you need.
You will be presented with a list of websites to choose from. The sites at the very top and along the right are adverts that people have paid to get their content, info or product offer in front of your eyes.
Under the top adverts are roughly ten websites listed. These are the SEO results and the websites the algorithm has chosen as the best to suit you.
Which is best for you if you are a website owner? If you have the time, invest in some training. If not get a reputable company to do it for you and try to learn as much as you can when you can along the way.