SEO or Search Engine Optimisation is the name given to activity that attempts to improve search engine rankings. In search results, Google™ displays link to pages it considers relevant and authoritative. Authority is mostly measured by analyzing the number and quality of links from other web pages. In simple terms, your web pages have the potential to rank in Google™ so long as other web pages link to them.
We've found that the factors in Google's algorithm can be divided into two main categories, which together determine the ranking of your website:
1. On-page SEO factors
On-page SEO factors are all those things you can influence from within your actual website. All manner of technical aspects of your website is important to improve the likelihood of your website ranking well in the search engines. WordPress is actually a pretty SEO-friendly platform. Combined with our Yoast SEO plugin, most technical challenges can be overcome.
The structure of your website, your site speed and the content of your site are all crucial on-page SEO factors. To find out about these all-important on-page ranking factors, have a look through the various categories of our SEO blog.
2. Off-page SEO factors
As well as on-page SEO factors, there are the off-page SEO factors. These off-page SEO factors are rather more difficult to influence, though. The most important of these off-page factors is the number and quality of links pointing towards your site. The more quality, relevant sites that link to your website, the higher your position in Google will be.
Another off-page factor is your competition relating to the niche of your particular business. In some niches, it is much harder to rank than in others. The competitiveness of your market therefore also has a major influence on your chances of ranking.
source: https://yoast.com/what-is-seo/