Google crawls website in the perspective of meta tags, keywords and from all of these google compares website into ranking system, and it matches contents of websites from all of these dependent information management so that search engines finds relevant information from yours website to find out relevant searching information.
When we install WordPress from the perspective of meta tags in normal installation but it can be added to themes from front end or back end installation of WordPress. Here, comes the most important information such as author of website, keywords related to yours website, description of website and copyright and all of these can be written at the footer of website.
Search engines cannot read all of these information from website separately, as it needs to be at the header of website theme so that search engines can read all of these information from coding into theme file and as the result of it, With the augment of modern websites and advance configuration of WordPress website more and more search engines find these information automatically.
Google no longer depend upon keyword optimization so putting manual key words into it does not take any importance but in other words some other webmaster tools might take advantage of it so it is important to go for implementation of these keyword tools so that each and every webmaster tools deals with yours website and find relevant information from it.
The content is king and the way content have it inside of yours website ranking system works with it so how so ever good keyword placing of your website but if its contents are not of high standard then automatically the ranks of website goes downside.
So, it is important to write content for the better information so that when website shows search results on specific terms when some one searches on search engines then it should have been good and better satisfied users so that they do not find any difficulties and reach to these systems in absolute terms.